Checklist

A-B-C

Achnanthes acares Hohn et Hellerman
   AZ (San Pedro River)

Achnanthes coarctata (Brébisson) Grunow
   AZ (Grand Canyon, Chevelon Creek, Oak Creek, West Clear Creek)
   NM (Aguirre Springs)

Achnanthes expressa J. R. Carter in Hartley
   AZ (West Clear Creek)

Achnanthes inflata (Kützing) Grunow
   AZ (Queen Creek)

Achnanthes minutissima var. jackii (Rabenhorst) Lange-Bertalot & Ruppel
   AZ (San Pedro River) [This taxon should be formally moved to Achnanthidium.]

Achnanthes pinnata Hustedt
   AZ (Rio Salado)   NM (Rito de Los Frijoles) [Taxonomic status unclear.]

Achnanthes ventralis var. crassa (Reimer) Lange-Bertalot
   SYN: Achnanthes sublaevis var. crassa Reimer in Patrick & Reimer
   AZ (Lake Powell, Grand Canyon)

Achnanthidium deflexum (Reimer) Kingston
   AZ (Grand Canyon, West Clear Creek)

Achnanthidium exiguum (Grunow) Czarnecki
   SYN:Achnanthes exigua Grunow in Cleve & Grunow, Achnanthes biasolettiana Grunow in Cleve & Grunow    AZ (Southern Arizona Lakes, Central Arizona Project, Cave Creek, Ayers Lake, Queen Creek, West Clear Creek, San Pedro River, Rio Salado, 91st Avenue WWTP, Santa Cruz River, Gila River, Verde River)   NM: (Rito de Los Frijoles, Rio Grande

Achnanthidium exiguum var. heterovalvum (Krasske) Czarnecki
   SYN: Achnanthes exigua var heterovalvata Krasske    AZ (Southern Arizona Lakes, Grand Canyon, Chevelon Creek, San Pedro River)   NM (Rio Brazos, Rio Grande)

Achnanthidium exile (Kützing) Bukhtiyarova
   SYN: Achnanthes exilis Kützing    AZ (San Pedro River, West Clear Creek   NM (Conchas Lake, Elephant Butte Lake)

Achnanthidium gracillimum (Meister) Lange-Bertalot
   SYN: Achnanthes minutissima var. gracillima (Meister) Lange-Bertalot    NM (Conchas Lake, Ute Lake)

Achnanthidium macrocephalum (Hustedt) Round & Bukhtiyarova
   SYN: Achnanthes minutissima var. macrocephala Hustedt    NM (Conchas Lake)

Achnanthidium microcephalum Kützing
   SYN: Achnanthes microcephala (Kützing) Grunow    AZ (Lake Powell, Grand Canyon, Upper Lake Mary)

Achnanthidium minutissimum (Kützing) Czarnecki
   SYN: Achnanthes minutissima Kützing    AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Chevelon Creek, Tonto Creek, San Pedro River, Rio Salado, 91st Avenue WWTP, Gila River, Santa Cruz River, Rio Verde, West Clear Creek)    NM (Conchas Lake, Elephant Butte Lake, Rio Grande, Embudo Creek, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos)

Achnanthidium minutissimum var. affinis (Grunow) Bukhtiyarova
   SYN: Achnanthes affinis Grunow; Achnanthidium affine (Grunow) Czarnecki    AZ (Lake Powell, Grand Canyon, Oak Creek, Chevelon Creek, Tonto Creek, Cave Creek, Queen Creek, San Pedro River, West Clear Creek)   NM (Rio Grande at Isleta, Rito de los Frijoles)

Achnanthidium rosenstockii (Lange-Bertalot) Lange-Bertalot
   SYN: Achnanthes rosenstockii Lange-Bertalot    NM (Conchas Lake)

Adlafia bryophila (Peterson) Moser, Lange-Bertalot & Metzeltin
   AZ (West Clear Creek)

Adlafia minuscula (Grunow) Lange-Bertalot in Lange Bertalot & Genkal
   SYN: Navicula minuscula Grunow in Van Heurck    AZ (Lake Powell, Grand Canyon, Rio Verde)

Amphicampa mirabilis Ehrenberg ex Ralfs in Pritchard
   AZ (Southern Arizona Lakes)

Amphipleura pellucida Kützing
   AZ (Oak Creek, Chevelon Creek, Grand Canyon, Lake Powell, Central Arizona Project, East Verde River, Cave Creek, Bartlett Lake)    NM (Conchas Lake, Rio Brazos, Santa Rosa Lake, Ute Lake, Rio Chama, Rio Grande)

Amphipleura sp. 1 -NAWQA
   AZ (San Pedro River)

Amphora copulata (Kützing) Schoeman & Archibald
   SYN: Amphora ovalis var. libyca (Ehrenberg) Cleve    AZ (Cave Creek, Ayers Lake, San Pedro River, West Clear Creek, Rio Salado, Rio Verde, Santa Cruz River, Bartlett Lake)    NM (Elephant Butte Lake)    W TX (Diamond Y Spring, Ft. Davis CDRI)

Amphora delicatissima Krasske in Hustedt
   AZ (Canyon Lake)    NM (McAllister Lake)

Amphora fogediana Krammer in Krammer & Lange-Bertalot
   NM (Rio Chama)

Amphora inariensis Krammer
   AZ (San Pedro River, Gila River, Rio Verde, West Clear Creek)

Amphora ovalis (Kützing) Kützing
   AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Chevelon Creek, East Verde River, San Pedro River, West Clear Creek)    NM (Elephant Butte Lake, Conchas Lake, Pecos River, Charette Lake, San Juan River, Ute Lake)

Amphora ovalis var. affinis (Kützing) Van Heurck
   AZ (Gila River)    NM (Rio Grande, Santa Rosa Lake, Charette Lake, San Juan River, Ute Lake)

Amphora ovalis var. gracilis (Ehrenberg) Van Heurck
   NM (Santa Rosa Lake)

Amphora pediculus (Kützing) Grunow in Schmidt
   SYN: Amphora ovalis var. pediculus (Kützing) Van Heurck    AZ (Grand Canyon, Peña Blanca Lake, Kinsley Lake (Southern Arizona Lakes), Chevelon Creek, Cave Creek, Rio Salado, East Verde River, San Pedro River, West Clear Creek)    NM (Rio Brazos, San Juan River, Jemez River, Rio Grande, Rattlesnake Spring)    W TX (Ft. Davis CDRI)

Amphora perpusilla (Grunow) Grunow in Van Heurck
   AZ (Grand Canyon, Southern Arizona Lakes, Chevelon Creek, San Pedro River, Rio Salado, Gila River, Santa Cruz River, Rio Verde, West Clear Creek)   NM (Conchas Lake, Rio Grande, Charette Lake, San Juan River, Santa Rosa Lake, Embudo Creek, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River. Rio Pueblo de Taos)

Amphora sp. 1 -NAWQA
   AZ (Gila River, Santa Cruz River)

Amphora sp. 1 -ANS WRC
   AZ (Canyon Lake)

Aneumastus tuscula (Ehrenberg) D. Mann & Stickle in Round et al.
   SYN: Navicula tuscula Ehrenberg    AZ (Grand Canyon)

Anomoeoneis costata (Kützing) Hustedt
   W TX (Diamond Y Spring)

Anomoeoneis sphaerophora Pfitzer
   SYN: Anomoeoneis sphaerophora (Kützing) Pfitzer    AZ (Chevelon Creek)    NM (Rio Grande, Charette Lake, Santa Fe River)

Anomoeoneis sphaerophora f. costata (Kützing) A.-M. Schmid
   AZ (Chevelon Creek)   NM (Elephant Butte Lake)

Astartiella cf. bahusiensis (Grunow) Witkowski, Lange- Bertalot & Metzeltin
   SYN: Achnanthes bahusiensis (Grunow) Lange-Bertalot in Lange-Bertalot & Krammer    AZ (Santa Cruz River)

Astartiella wellsiae (Reimer) Witkowski & Lange- Bertalot
   SYN: Achnanthes wellsiae Reimer in Patrick & Reimer    AZ (Grand Canyon)

Asterionella formosa Hassall
   AZ (Chevelon Creek, Sunrise Lake, Big Lake, Canyon Lake, Saguaro Lake)    NM (Conchas Lake, Charette Lake, San Juan River, Santa Rosa Lake, Jemez River, Rio Grande)    W TX (Ft. Davis CDRI)

Asterionella sp.
   NM (Elephant Butte Lake)

Aulacoseira alpigena (Grunow) Krammer
   SYN: Melosira distans var. alpigena Grunow in Van Heurck    AZ (Chevelon Creek)    NM (Pecos River, San Juan River?)

Aulacoseira ambigua (Grunow) Simonsen
   SYN: Melosira ambigua (Ehrenberg)Müller    NM (Conchas Lake, Rio Chama, Jemez River, Rio Grande)

Aulacoseira crenulata (Ehrenberg) Thwaites
   SYN: Melosira crenulata (Ehrenberg) Kützing    NM (Rio Brazos)

Aulacoseira granulata (Ehrenberg) Simonsen
   SYN: Melosira granulata (Ehrenberg) Ralfs in Pritchard    AZ (Canyon Lake)    NM (Rio Chama, McAllister Lake, Rio Grande, Charette Lake, San Juan River, Ute Lake, Santa Rosa Lake)

Aulacoseira granulata var. angustissima (O. Müller) Simonsen
   SYN: Melosira granulata var. angustissima O. Müller    AZ (Canyon Lake)

Aulacoseira granulata f. spiralis (Hustedt) Czarnecki & Reinke
   SYN: Melosira granulata f. spiralis Grunow    NM (Elephant Butte Lake)

Aulacoseira italica (Ehrenberg) Simonsen
   SYN: Melosira italica (Ehrenberg) Kützing    NM (Rio Brazos, Rio Grande)

Aulacoseira italica var. tenuissima (Grunow) Simonsen
   SYN: Melosira italica var. tenuissima (Grunow) Müller    NM (Rio Grande)

Aulacoseira muzzanensis (Meister) Krammer
   NM (Rio Brazos)

Aulacoseira subarctica (O. Müller) Haworth
   NM (Rio Brazos)

Bacillaria paxillifera (O.F. Müller) Hendey
   SYN: Bacillaria paradoxa Gmelin in Linnaeus   AZ (Grand Canyon, Canyon Lake, Chevelon Creek, Rio Verde, San Pedro River, Rio Salado, Gila River, Rio Verde)   NM (Ute Lake, Rio Grande)

Bacillaria socialis (Gregory) Ralfs in Pritchard
   SYN: Nitzschia socialis Gregory    NM (Elephant Butte Lake?, McAllister Lake, Rio Grande)

Berkeleya rutilans (Trentepohl ex Roth) Grunow
   SYN: Amphipleura rutilans (Trentepohl ex Roth) Cleve    AZ (San Pedro River)

Biremis circumtexta (Meister ex Hustedt) R. Ross in Patrick & Reimer
   SYN: Navicula circumtexta Meister ex Hustedt    NM (Rio Chama)

Brachysira vitrea (Grunow) R. Ross in Hartley
   SYN: Anomoeoneis vitrea (Grunow) R. Ross in Patrick & Reimer    AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes)    NM (Conchas Lake, Red River)

Caloneis amphisbaena (Bory) Cleve
   AZ (Lake Powell, Grand Canyon, Chevelon Creek)   NM (State record, Vallecito River, Rio Grande, Charette Lake, Jemez River)

Caloneis amphisbaena f. subsalina (Donkin) Van der Werff & Huls
   AZ (Chevelon Creek)

Caloneis bacillaris (Gregory) Cleve
   AZ (Chevelon Creek)    NM (San Juan River, Pecos River, Ute Lake)

Caloneis bacillum (Grunow) Cleve
   AZ (Grand Canyon, Chevelon Creek, Cave Creek, San Pedro River, Rio Verde, West Clear Creek)    NM (Conchas Lake, Elephant Butte Lake, Rio Grande, Rio Brazos, San Juan River, Embudo Creek, Rio Chama, Rito de los Frijoles, Santa Fe River)

Caloneis backmanii Cleve-Euler in Backman & Cleve-Euler
   AZ (Grand Canyon)

Caloneis budensis (Grunow) Krammer in Krammer & Lange-Bertalot
   AZ (Cave Creek, West Clear Creek)

Caloneis cf. hultenii Petersen
   AZ (Queen Creek)    NM (Aguirre Springs)

Caloneis hyalina Hustedt
   AZ (Grand Canyon, Chevelon Creek, East Verde River)

Caloneis lancettula (Schulz) Lange-Bertalot & Witkowski
   SYN: Caloneis bacillum var. lancettula (Schulz) Hustedt    NM (Elephant Butte Lake)

Caloneis latiuscula var. reimeri Czarnecki & Blinn
   AZ (Montezuma Well)

Caloneis lewisii Patrick
   AZ (Big Lake Outlet, Lake Powell, East Verde River, Cave Creek, A-1 Lake, Bartlett Lake)    NM (Rio Brazos, Santa Rosa Lake, Rio Grande)

Caloneis lewisii var. inflata (Schultze) Patrick
   NM (Abiquiu Lake, Conchas Lake)

Caloneis limosa (Kützing) Patrick
   AZ (Lake Powell, Chevelon Creek, Queen Creek, San Pedro River, West Clear Creek)    NM (Pecos River, Rio Grande, Rio Brazos, Santa Rosa Lake)

Caloneis macedonica Hustedt
   AZ (West Clear Creek)

Caloneis molaris (Grunow) Krammer in Krammer & Lange-Bertalot
   NM (Conchas Lake)

Caloneis oregonica (Ehrenberg) Patrick
   AZ (Chevelon Creek)

Caloneis patagonica (Cleve) Cleve
   NM (Conchas Lake)

Caloneis permagna (Baily) Cleve
  W TX (East Sandia Spring)

Caloneis pulchra var. brevistriata (O. Müller) Cleve Euler
   AZ (Grand Canyon)

Caloneis sp. cf. speciosa (Hustedt) Boyer
   AZ (Big Lake Outlet)

Caloneis thermalis (Grunow) Krammer in Krammer & Lange-Bertalot
   SYN: Caloneis bacillaris var. thermalis (Grunow) A. Cleve-Euler    AZ (Grand Canyon)    NM (Conchas Lake, Pecos River, Rio Grande)

Caloneis undulata (Gregory) Krammer in Krammer & Lange-Bertalot
   NM (Conchas Lake)

Caloneis ventricosa (Ehrenberg) Meister
   SYN: Caloneis silicula (Ehrenberg) Cleve    AZ (Lake Powell, San Pedro River, West Clear Creek)    NM (Conchas Lake, Rio Brazos, Ute Lake)

Caloneis ventricosa var. alpina (Cleve) Patrick
   NM (Rio Grande)

Caloneis ventricosa var. minuta (Grunow) Mills
   AZ (Sunrise Lake)    NM (Elephant Butte Lake, Conchas Lake, Rio Brazos)

Caloneis ventricosa var. subundulata (Grunow) Patrick
   NM (Elephant Butte Lake, Cochiti Lake, Conchas Lake, Rio Brazos)

Caloneis ventricosa var. truncatula (Grunow) Meister
   AZ (Lake Powell, Grand Canyon, Cave Creek)    NM (McAllister Lake, Pecos River, Rio Chama, Jemez River, Rio Grande)

Caloneis ventricosa var.tumida (Hustedt) Foged
   SYN: Caloneis silicula var. tumida Hustedt    AZ (Lake Powell)

Caloneis sp. 1 -NAWQA
   AZ (San Pedro River, West Clear Creek?)

Campylodiscus clypeus (Ehrenberg) Kützing
   AZ (Chevelon Creek)    NM (Bitter Lake)    W TX (East Sandia Spring)

Campylodiscus hibernicus Ehrenberg
   SYN: Campylodiscus noricus var. hibernica (Ehrenberg) Grunow    AZ (Grand Canyon, East Verde River, West Clear Creek)

Cavinula cocconeiformis (Gregory ex Greville) D. Mann & Stickle
   SYN: Navicula cocconeiformis Gregory ex Greville    AZ (Grand Canyon, Chevelon Creek, San Pedro River)    NM (Charette Lake)

Cavinula variostriata (Krasske) D. Mann in Round et al.
   SYN: Navicula variostriata Krasske    AZ (Sheep's Crossing)

Ceratoneis closterium Ehrenberg
   SYN: Nitzschia closterium (Ehrenberg) W. Smith    AZ (Canyon Lake)

Ceratoneis gracilis Brébisson ex Kützing
   SYN: Cylindrotheca gracilis (Brébisson) Grunow    AZ (Lake Powell, Grand Canyon, Cholla Lake, Chevelon Creek, San Pedro River, Rio Salado)

Ceratoneis reversa (W. Smith) Ralfs in Pritchard
   SYN: Nitzschia reversa W. Smith    AZ (San Pedro River, Rio Salado, Rio Verde)    NM (McAllister Lake, Rio Grande)

Cestodiscus denarius (Schmidt) Strelnikova & Fourtanier
   SYN: Coscinodiscus denarius Schmidt    AZ (Grand Canyon) [Doubtful, possibly a Thalassiosira sp.?]

Chaetoceros minimus (Levander) Marino, Giuffre, Montresor & Zingone
   SYN: Rhizosolenia minima Levander    AZ (Chevelon Creek)

Chaetoceros muelleri Lemmermann
   AZ (Chevelon Creek)

Chamaepinnularia soehrensis var. muscicola (Petersen) Lange-Bertalot & Krammer
   AZ (San Pedro River)

Cocconeis disculus (Schumann) Cleve in Cleve & Jentzsch
   AZ (Oak Creek)    NM (Elephant Butte Lake)

Cocconeis disculus var. diminuta (Pantocsek) Cleve Euler
   AZ (Grand Canyon, Chevelon Creek)

Cocconeis fluviatilis Wallace
   NM (San Juan River, Santa Fe River, Rio Grande)

Cocconeis neothumensis Krammer
   NM (Conchas Lake)

Cocconeis pediculus Ehrenberg
   AZ (Southern Arizona Lakes, Central Arizona Project, Grand Canyon, Oak Creek, Canyon Lake, Chevelon Creek, East Turkey Creek, Sycamore Creek, East Verde River, Tonto Creek, Cave Creek, Rio Verde, Rio Salado, San Pedro River, Gila River, West Clear Creek)   NM (Rio Chama, Navajo Lake, Elephant Butte Lake, Brantley Lake, Conchas Lake, McAllister Lake, Rio Grande, Santa Rosa Lake, Charette Lake, San Juan River, Embudo Creek, Jemez River, Rito de Los Frijoles, Santa Fe River, Rio Pueblo de Taos)    W TX (Ft. Davis CDRI)

Cocconeis placentula Ehrenberg
   AZ (Lake Powell, Peña Blanca Lake, San Pedro River, Rio Salado, Gila River, Santa Cruz River, Rio Verde, West Clear Creek)    NM (State record, Conchas Lake, Elephant Butte Lake, Rio Grande)

Cocconeis placentula var. euglypta (Ehrenberg) Grunow
   AZ (Lake Powell, Southern Arizona Lakes, Chevelon Creek, East Turkey Creek, East Verde River, Tonto Creek, Oak Creek, Cave Creek, Rio Verde, San Pedro River, Rio Salado, West Clear Creek)    NM (Carlito Spring, Elephant Butte Lake, Railroad Canyon, Rio Chama, McAllister Lake, Rio Grande, Rio Brazos, Charette Lake, San Juan River, Ute Lake, Embudo Creek, Jemez River, Rito de Los Frijoles, Santa Fe River, Rio Pueblo de Taos)

Cocconeis placentula var. lineata (Ehrenberg) Van Heurck
   AZ (Southern Arizona Lakes, Central Arizona Project, Grand Canyon, Oak Creek, Chevelon Creek, Sunrise Lake, Ayers Lake, Queen Creek, Rio Salado, East Verde River, San Pedro River, Gila River, Rio Verde, West Clear Creek)    NM (Rio Grande, Rio Brazos, Charette Lake, San Juan River, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Rattlesnake Spring)    W TX (Ft. Davis CDRI)

Craticula accomoda (Hustedt) D. Mann in Round et al.
   SYN: Navicula accomoda Hustedt    AZ (Lake Powell, Grand Canyon, Chevelon Creek, Cave Creek, San Pedro River)    NM (Charette Lake, McAllister Lake, San Juan River, Ute Lake, Aguirre Spring, Rio Grande)

Craticula ambigua (Ehrenberg) D. Mann in Round et al.
   SYN: Navicula cuspidata var. ambigua (Ehrenberg) Cleve    AZ (Sycamore Creek, East Verde River, Cave Creek, Ayers Lake, Queen Creek, Bartlett Lake, Rio Verde, Santa Cruz River)    NM (Charette Lake, Aguirre Springs, Conchas Lake, Elephant Butte Lake, Rio Grande)

Craticula cuspidata (Kützing) D. Mann in Round et al.
   SYN: Navicula cuspidata (Kützing) Kützing    AZ (Lake Powell, Southern Arizona Lakes, Central Arizona Project, Grand Canyon, Upper Lake Mary, Chevelon Creek, San Pedro River, 91st Avenue WWTP, Gila River)    NM (Rio Chama, Charette Lake, San Juan River, Elephant Butte Lake, Conchas Lake, Rio Grande, Rio Brazos, Santa Rosa Lake, Jemez River, Santa Fe River)    W TX (Laguna Prieta)

Craticula cuspidata var. major (Meister) Czarnecki
   AZ (Grand Canyon)

Craticula halophila (Grunow ex Van Heurck) D. Mann in Round et al.
   SYN: Navicula halophila (Grunow) Cleve    AZ (Southern Arizona Lakes, Chevelon Creek, San Pedro River, Santa Cruz River)    NM (Cochiti Lake, Ute Lake?, Conchas Lake, McAllister Lake, Rio Grande?, Rio Brazos)

Craticula halophila f. subcapitata (Østrup) Czarnecki
   SYN: Navicula halophila var. subcapitata Østrup    AZ (Southern Arizona Lakes)

Craticula molestiformis (Hustedt) Mayama
   SYN: Navicula molestiformis Hustedt    AZ (San Pedro River, West Clear Creek)

Craticula riparia (Hustedt) Lange-Bertalot
   SYN: Navicula riparia Hustedt    AZ (San Pedro River)

Ctenophora pulchella (Ralfs ex Kützing) Williams & Round
   SYN: Synedra pulchella Ralfs ex Kützing   AZ (Chevelon Creek)   NM (Conchas Lake, McAllister Lake, Ute Lake)

Ctenophora pulchella var. lacerata (Hustedt in Schmidt) Bukhtiyarova
   SYN: Synedra pulchella var. lacerata Hustedt in Schmidt   AZ (Rip Salado)

Cyclostephanos dubius (Fricke) Round
   SYN: Cyclotella dubia Fricke    AZ (San Pedro River)

Cyclostephanos invisitatus (Hohn & Hellerman) Theriot, Stoermer & Hâkansson
   SYN: Stephanodiscus invisitatus Hohn & Hellerman    AZ (Chevelon Creek, Rio Salado)   NM (Rio Grande)

Cyclostephanos tholiformis Stoermer, Hâkansson & Theriot
   AZ (San Pedro River)

Cyclostephanos sp. 1 -NAWQA
   AZ (San Pedro River)

Cyclotella affiniformis Krammer
   AZ (Bartlett Lake)

Cyclotella atomus Hustedt
   AZ (Grand Canyon, Saguaro Lake, Canyon Lake, Rio Verde, Rio Salado, San Pedro River)   NM (Rio Brazos, Rio Grande)

Cyclotella bodanica var. lemanica (O. Müller) Bachmann
   NM (San Juan River) [Since C. bodanica was moved by Håkansson to the new genus Puncticulata, this variety and the one following are in limbo. Presumably, if they are valid taxa, they should be formally moved also.]

Cyclotella bodanica var. michiganensis Skvortzow
   AZ (Lake Powell)

Cyclotella distinguenda Hustedt
   NM (Rio Brazos)

Cyclotella hakanssoniae Wendker
   NM (Conchas Lake, Elephant Butte Lake)

Cyclotella michiganiana Skvortzow
   AZ (Lake Powell, Grand Canyon)    NM (Rio Grande)

Cyclotella ocellata Pantocsek
   NM (Conchas Lake, Pecos River, San Juan River, Ute Lake)

Cyclotella pseudonana (Hasle & Heimdal) Chang in Chang & Steinberg
   SYN: SYN: Thalassiosira pseudonana Hasle & Heimdal    AZ (Chevelon Creek, San Pedro River)

Cyclotella pseudostelligera f. parva Czarnecki & Blinn
   AZ (Montezuma Well) [Since C. pseudostelligera has been placed in the genus Discostella, this form should be formally moved there also.]

Cyclotella striata (Kützing) Grunow in Cleve & Grunow
   AZ (Canyon Lake)

Cymatopleura cochlea Brun
   W TX (Ft. Davis CDRI)

Cymatopleura elliptica (Brébisson) W. Smith
   AZ (Southern Arizona Lakes, Chevelon Creek, East Verde River, Bartlett Lake, Rio Verde)    NM (Santa Rosa Lake)

Cymatopleura elliptica f. spiralis Boyer
   AZ (East Verde River)

Cymatopleura solea (Brébisson) W. Smith
   AZ (Lake Powell, Grand Canyon, Oak Creek, Chevelon Creek, Bartlett Lake, San Pedro River, Rio Salado, West Clear Creek)    NM (Rio Chama, San Juan River, Elephant Butte Lake, Conchas Lake, Rio Grande, Rio Brazos, Charette Lake, Ute Lake, Santa Rosa Lake, Jemez River, Rio Grande, Rio Pueblo de Taos)    W TX (Ft. Davis CDRI)

Cymatopleura solea var. apiculata (W. Smith) Ralfs in Pritchard
   AZ (Lake Powell, East Verde River, Cave Creek, Oak Creek, Bartlett Lake, San Pedro River, Gila River)    NM: (Elephant Butte Lake, Cochiti Lake, Conchas Lake, Charette Lake)

Cymbella affinis Kützing
   SYN: Cymbella tumidula Grunow in Schmidt    AZ (Lake Powell, Southern Arizona Lakes, Central Arizona Project, Grand Canyon, Oak Creek, Beaver Creek, Upper Lake Mary, Rio Verde, San Pedro River, Rio Salado, Gila River, West Clear Creek)   NM (State record, Rio Chama, Elephant Butte Lake, Conchas Lake, Santa Rosa Lake, Ute Lake, San Juan River, McAllister Lake, Rio Brazos, Embudo Creek, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Grande, Rio Pueblo de Taos)

Cymbella australica (A. Schmidt) Cleve
   SYN: Cymbella tumida var. gracilis Hustedt    NM (Rio Grande, Rio Brazos) [Krammer claimed this synonymy, but C. australis is regarded as Australasian in its distribution.]

Cymbella cistula (Hemprich in Hemprich & Ehrenberg) Kirchner
   AZ (Lake Powell, Central Arizona Project, Grand Canyon, Chevelon Creek, West Clear Creek)   NM (McAllister Lake, Rio Grande, Rio Brazos, Santa Rosa Lake) [According to Krammer this name represents three separate taxa: Cymbella subcistula Krammer, Cymbella neocistula Krammer, and Cymbella dorsenotata Østrup. Specimens will need to be reexamined to confirm proper identifications.]

Cymbella cymbiformis Agardh
   SYN: Cymbella cymbiformis var. nonpunctata Fontell, Cymbella cistula var. gibbosa Brun    AZ (Chevelon Creek)    NM (Conchas Lake, Rio Grande?, Ute Lake, Pecos River, Rio Brazos Santa Rosa Lake)

Cymbella excisa Kützing
  AZ (East Verde River, Cave Creek, Rio Verde)   NM (Rio Grande, Charette Lake)

Cymbella gracilis (Ehrenberg) Kützing
   AZ (San Pedro River, Gila River)    Note: There seems to be some confusion about this taxon as it is listed as Encyonema gracile Rabenhorst by several authorities

Cymbella helvetica Kützing
   AZ (Southern Arizona Lakes)

Cymbella hustedtii Krasske
   NM (Conchas Lake)

Cymbella janischii (A. Schmidt) De Toni
  SYN: Cymbella mexicana var. jansichii (A. Schmidt) Reimer in Patrick & Reimer    AZ (West Clear Creek)

Cymbella kolbei Hustedt
   AZ (Quitobaquito Spring)   NM (Aguirre Spring)

Cymbella laevis Nögeli in Rabenhorst
   AZ (Lake Powell, Grand Canyon)

Cymbella lanceolata (Agardh) Agardh
   NM (Ute Lake)

Cymbella leptoceros (Ehrenberg) Kützing
   AZ (Grand Canyon, Southern Arizona Lakes) [Krammer suggests that this epithet is unrecognizable. Specimens need to be reexamined to provide a proper identification.]

Cymbella mexicana (Ehrenberg) Cleve
   AZ (Central Arizona Project, Grand Canyon, Oak Creek, Canyon Lake, Chevelon Creek, Cave Creek, West Clear Creek)   NM (State record, Elephant Butte Lake, Rio Grande, San Juan River, Ute Lake, Rio Chama)

Cymbella mexicana var. kamtschatica (Grunow) Krammer
   AZ (Colorado River, Rio Salado)

Cymbella microcephala var. crassa Reimer
   AZ (Lake Powell, Grand Canyon) [Apparently not formally moved to Encyonopsis.]

Cymbella parva (W. Smith) Kirchner
   AZ (Grand Canyon, Oak Creek)

Cymbella proximaReimer in Patrick & Reimer
   NM (Charette Lake)

Cymbella proxima f. gravida Reimer in Patrick & Reimer
   NM (Charette Lake)

Cymbella subturgidula Krammer
   AZ (West Clear Creek, Hawley Lake)

Cymbella tumida (Brébisson ex Kützing) Van Heurck
   SYN: Cymbella tumida var. borealis (Grunow) Cleve    AZ (Grand Canyon, Cave Creek, San Pedro River, Gila River, Rio Verde, West Clear Creek, East Verde River, Bartlett Lake)    NM (Rio Chama, Elephant Butte Lake, Conchas Lake, McAllister Lake, Rio Grande, Rio Brazos, Charette Lake, San Juan River, Santa Rosa Lake)

Cymbella turgidula Grunow in Schmidt
   AZ (Rio Salado, Gila River, Rio Verde, West Clear Creek)   NM (Conchas Lake, San Juan River, Santa Rosa Lake)

Cymbella sp. 4 -ANS
   NM (Rio Pueblo de Taos)

Cymbellafalsa diluviana (Krasske) Lange-Bertalot & Metzeltin
   SYN: Cymbella diluviana (Krasske) Florin   AZ (Santa Cruz River)   NM (Conchas Lake)

Cymbopleura amphicephala (Nägeli) Krammer
   SYN: Cymbella amphicephala Nögeli ex Kützing    AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes)    NM (State record, Conchas Lake, Rio Chama)

Cymbopleura angustata (W. Smith) Krammer
   SYN: Navicula angustata W. Smith, Cymbella angustata (W. Smith) Cleve    NM (Rio Grande)

Cymbopleura austriaca (Grunow) Krammer
   SYN: Cymbella austriaca Grunow in Schmidt    NM (Conchas Lake)

Cymbopleura inaequalis (Ehrenberg) Krammer
   SYN: Cymbella inaequalis (Ehrenberg) Rabenhorst    AZ (Sheep's Crossing)   NM (Conchas Lake, Pecos River)

Cymbopleura lata (Grunow) Krammer
   SYN: Cymbella lata Grunow in Cleve    NM (Elephant Butte Lake)

Cymbopleura naviculiformis (Auerswald) Krammer
   SYN: Cymbella naviculiformis (Auerswald) Cleve    AZ (Big Lake Outlet, Southern Arizona Lakes)    NM (Pecos River, Rio Grande, Rio Brazos)

D-E-F

Decussata placenta (Ehrenberg) Lange-Bertalot
   SYN: Navicula placenta (Ehrenberg) Ralfs in Pritchard    AZ (San Pedro River, West Clear Creek)

Denticula delicatula (Kützing) Krammer
   AZ (San Pedro River)

Denticula elegans Kützing
   AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Oak Creek, Beaver Creek, Chevelon Creek)    NM (State record, Conchas Lake, Elephant Butte Lake, Rio Grande at Rinconada)

Denticula kuetzingii Grunow
   SYN: Nitzschia denticula Grunow in Cleve & Grunow    AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Rio Verde, West Clear Creek, Cave Creek)    NM (Conchas Lake, La Cienega Lake, Rattlesnake Spring)

Denticula kuetzingii var. rumrichae Krammer in Lange-Bertalot & Krammer
   AZ (San Pedro River, Santa Cruz River, Rio Verde, West Clear Creek)

Denticula subtilis Grunow
   SYN: Denticula rainierensis Sovereign    AZ (Lake Powell, Grand Canyon, Chevelon Creek)

Denticula tenuis Kützing
   NM (Elephant Butte Lake)

Denticula tenuis var. crassula (Nägeli in Kützing) West & West
   NM (Elephant Butte Lake)

Denticula thermalis Kützing
  AZ (Chevelon Creek)

Diadesmis confervacea Kützing
  SYN: Navicula confervacea (Kützing) Grunow    AZ (Chevelon Creek, West Clear Creek, San Pedro River, 91st Avenue WWTP, Santa Cruz River)   NM (Santa Fe River, Rio Grande)

Diadesmis contenta var. biceps (Grunow) Hamilton in Hamilton et. al.
  SYN: Navicula contenta var. biceps (Grunow) Van Heurck    NM (Rito de Los Frijoles, Rio Grande)

Diatoma hiemale (Lyngbye) Heiberg
   NM (Pecos River, San Juan River)

Diatoma mesodon (Ehrenberg) Kützing
   SYN: Diatoma hiemale var. mesodon (Ehrenberg) Kirchner    AZ (Grand Canyon, Oak Creek, Tonto Creek)    NM (San Juan River, Pecos River, Rio Grande, Rito de Los Frijoles)

Diatoma moniliformis Kützing
   AZ (Rio Verde)

Diatoma tenue Agardh
   AZ (Chevelon Creek, Big Lake)    NM (Elephant Butte Lake, Charette Lake, San Juan River)

Diatoma tenue var elongatum Lyngbye
   NM (Rio Chama, Elephant Butte Lake, Conchas Lake, Rio Grande, San Juan River, Ute Lake, Santa Rosa Lake, Santa Fe River, Jemez River)

Diatoma vulgare Bory
   AZ (Grand Canyon, Southern Arizona Lakes, Central Arizona Project, Oak Creek, Canyon Lake, East Verde River, Queen Creek, Cave Creek, Bartlett Lake, Rio Verde, Rio Salado, Gila River, Santa Cruz River, West Clear Creek, San Pedro River)    NM (State record, Rio Chama, San Juan River, Conchas Lake, McAllister Lake, Rio Brazos, Charette Lake, Embudo Creek, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Grande, Rio Pueblo de Taos)

Diatoma vulgare f. breve (Grunow) Bukhtiyarova
   NM (Rio Chama, Elephant Butte Lake, San Juan River)

Diatoma vulgare f. lineare (Grunow in Van Heurck) Hustedt
   NM (Rio Chama, Rio Grande, Rio Brazos)

Diatomella balfouriana Greville
   NM (Rio Grande, Rio Brazos)

Diploneis cf. boldtiana Cleve
   NM (Carlito Spring)

Diploneis elliptica (Kützing) Cleve
   AZ (Grand Canyon, West Clear Creek)    NM (Charette Lake, San Juan River, Ute Lake, Rito de Los Frijoles)

Diploneis interrupta (Kützing) Cleve
   AZ (Chevelon Creek)

Diploneis marginestriata Hustedt
   NM (Ute Lake)

Diploneis oblongella (Nägeli ex Kützing) Ross
   AZ (Grand Canyon)

Diploneis oculata (Brébisson) Cleve
   AZ (Lake Powell, Grand Canyon)    NM (Conchas Lake)

Diploneis parma Cleve
   AZ (Rio Salado)    NM (Ute Lake)

Diploneis pseudovalis Hustedt
   AZ (Chevelon Creek)    NM (Santa Rosa Lake)

Diploneis puella (Schumann) Cleve
   AZ (Lake Powell, Grand Canyon, Upper Lake Mary, Canyon Lake, Chevelon Creek)   NM (Conchas Lake, Elephant Butte Lake, Ute Lake, Jemez River, Rio Grande)

Diploneis smithii (Brébisson in W. Smith) Cleve
   AZ (Oak Creek, Canyon Lake)   NM (Conchas Lake, Elephant Butte Lake)

Diploneis smithii var. dilatata (M. Peragallo) Terry
   AZ (Grand Canyon, Canyon Lake)    NM (Conchas Lake, Ute Lake)

Diploneis subovalis Cleve
   NM (Santa Rosa Lake, Ute Lake, Jemez River)

Discostella glomerata (Bachmann) Houk & Klee
   SYN: Cyclotella glomerata Bachmann    AZ (Oak Creek)

Discostella pseudostelligera (Hustedt) Houk & Klee
   SYN: Cyclotella pseudostelligera Hustedt    AZ (Lake Powell, Saguaro Lake, Ayers Lake, San Pedro River, West Clear Creek)   NM (Jemez River, Rio Grande)

Discostella stelligera (Cleve & Grunow) Houk & Klee
   AZ (San Pedro River

Ellerbeckia arenaria f. teres (Brun) Crawford
   AZ (Oak Creek)

Encyonema auerswaldii Rabenhorst
   SYN: Cymbella prostrata var. auerswaldii (Rabenhorst) Reimer    AZ (Rio Verde, Hawley Lake, Canyon Lake)    NM (Elephant Butte Lake, Rio Grande, Rio Chama)

Encyonema brehmii (Hustedt) D. Mann in Round et al.
   SYN: Cymbella brehmii Husted    NM (Pecos River, San Juan River, Rio Chama, Santa Fe River, Red River)

Encyonema caespitosum Kützing
   SYN: Cymbella caespitosa (Kützing) Brun    NM (Rio Brazos)

Encyonema inelegans (Cleve) Mills
   SYN: Cymbella inelegans Cleve    NM (Elephant Butte Lake)

Encyonema lunatum (W. Smith) Van Heurck
   SYN: Cymbella lunata W.Smith    AZ (Sheep's Crossing)   NM (Pecos River, San Juan River)

Encyonema mesianum (Cholnoky) D. Mann in Round et al.
   NM (Santa Rosa Lake)

Encyonema minutum (Hilse in Rabenhorst) D. Mann in Round et al.
   SYN: Cymbella minuta Hilse in Rabenhorst   AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Upper Lake Mary, Oak Creek, Chevelon Creek, Tonto Creek, Cave Creek, Rio Verde, San Pedro River, West Clear Creek)   NM (Rio Chama, San Juan River, McAllister Lake, Rio Grande, Rio Brazos?, Ute Lake, Embudo Creek, Jemez River, Santa Fe River, Red River, Rio Pueblo de Taos)

Encyonema minutum var. pseudogracilis (Cholnoky) Czarnecki
   NM (Elephant Butte Lake, San Juan River)

Encyonema muelleri (Hustedt) D. Mann in Round et al.
   SYN: Cymbella muelleri Hustedt    NM (Conchas Lake, Rio Brazos, San Juan River, Ute Lake, Santa Rosa Lake, Jemez River)

Encyonema muelleri f. ventricosa (Tempère & Peragallo) Czarnecki
   SYN: Cymbella muelleri f. ventricosa (Tempère & Peragallo) Reimer    NM (Elephant Butte Lake)

Encyonema norvegica (Grunow in Schmidt) Bukhtiyarova
   SYN: Cymbella norvegica Grunow in Schmidt    AZ (Lake Powell, Grand Canyon)

Encyonema prostratum (Berkeley) Kützing
   SYN: Cymbella prostrata (Berkeley) Grunow    AZ (Grand Canyon, Southern Arizona Lakes, Chevelon Creek, East Verde River, San Pedro River, West Clear Creek)   NM (Elephant Butte Lake, Conchas Lake, Rio Grande, Rio Chama, Santa Rosa Lake, San Juan River, Rito de Los Frijoles)

Encyonema reichardtii (Krammer) D. Mann in Round et al.
   SYN: Cymbella reichardii Cymbella reichardtii Krammer in Krammer & Lange-Bertalot    AZ (Rio Verde)

Encyonema silesiacum (Bleisch ex Rabenhorst) D. Mann in Round et al.
   SYN: Cymbella minuta var. silesiaca (Bleisch ex Rabenhorst) Reimer    AZ (Sheep's Crossing, San Pedro River, West Clear Creek) NM (Rio Chama, Santa Rosa Lake, Elephant Butte Lake, Conchas Lake, Rio Grande, Rio Brazos, San Juan River, Santa Fe River, Red River)

Encyonema triangulum (Ehrenberg) Kützing
   AZ (Chevelon Creek)

Encyonema turgidum (Gregory) Grunow in Schmidt
   AZ (Southern Arizona Lakes)

Encyonema ventricosum (Kützing) Grunow in Schmidt
   AZ (Oak Creek)    NM (Elephant Butte Lake)

Encyonopsis falaisensis (Grunow) Krammer
   SYN: Cymbella falaisensis (Grunow) Krammer & Lange-Bertalot    AZ (Rio Salado)

Encyonopsis microcephala (Grunow) Krammer
   SYN: Cymbella microcephala Grunow in Van Heurck    AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Chevelon Creek, Ayers Lake, East Verde River, Rio Verde, San Pedro River, West Clear Creek)    NM (Conchas Lake, Ute Lake, Santa Rosa Lake, Embudo Creek, Rio Grande)

Entomoneis alata (Ehrenberg) Ehrenberg
   AZ (Grand Canyon, Cholla Lake, Chevelon Creek, Rio Verde)

Entomoneis ornata (Bailey) Reimer in Patrick & Reimer
   AZ (Upper Lake Mary, Ashurst Lake, Hawley Lake, A-1 Lake, Rio Salado)

Entomoneis paludosa (W. Smith) Reimer in Patrick & Reimer
   AZ (Lake Powell, Grand Canyon, Cholla Lake, Chevelon Creek)

Eolimna minima (Grunow in Van Heurck) Lange Bertalot in Moser et al.
   SYN: Navicula minima Grunow in Van Heurck    AZ (Grand Canyon, Chevelon Creek, Cave Creek, Rio Verde, East Verde River, San Pedro River, 91st Avenue WWTP, Santa Cruz River, West Clear Creek)   NM (Embudo Creek, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Rio Grande)

Eolimna subminuscula (Manguin) Moser, Lange-Bertalot & Metzeltin
   SYN: Navicula subminuscula Manguin, Navicula luzonensis Hustedt    AZ (Tonto Creek, Queen Creek, San Pedro River, Rio Salado, 91st Avenue WWTP, Santa Cruz River, West Clear Creek)    NM (Charette Lake, Rio Chama, Jemez River, Santa Fe River, Rio Grande)

Eolimna aff. subminuscula (Manguin) Moser, Lange-Bertalot & Metzeltin
   SYN: Navicula aff. subminuscula ANS NAWQA    AZ (San Pedro River, West Clear Creek)

Eolimna tantula (Hustedt) Lange-Bertalot in Werum & Lange-Bertalot
   SYN: Navicula tantula Hustedt    AZ (Cave Creek)   NM (Rio Chama, Rito de Los Frijoles, Rio Grande)

Epithemia adnata (Kützing) Brébisson
   SYN: Epithemia zebra var. proboscidea (Kützing) Grunow, Epithemia adnata var. minor (Peragallo & Héribaud) Patrick, Epithemia adnata var. porcellus (Kützing) Patrick, Epithemia adnata var. proboscidea (Kützing) Patrick    AZ (Grand Canyon, Southern Arizona Lakes, Upper Lake Mary, Chevelon Creek, Sunrise Lake, Ayers Lake, San Pedro River, Rio Salado, Rio Verde, West Clear Creek, Sycamore Creek)   NM (Santa Rosa Lake, Charette Lake?, Conchas Lake, San Juan River, Elephant Butte Lake, McAllister Lake, Rito de Los Frijoles)

Epithemia argus (Ehrenberg) Kützing
   SYN: Epithemia argus var. longicornis (Ehrenberg) Grunow    AZ (Lake Powell, Grand Canyon, Chevelon Creek) NM (State record, Rio Brazos)

Epithemia argus var. alpestris (W. Smith) Grunow
   AZ (Grand Canyon, Chevalon Creek)    NM (Elephant Butte Lake, Rio Brazos, Ute Lake, Santa Rosa Lake)

Epithemia frickei Krammer
   SYN: Epithemia intermedia Fricke in Schmidt    NM (Elephant Butte Lake, Rio Grande)

Epithemia goeppertiana Hilse
   AZ (San Pedro River, West Clear Creek)

Epithemia hyndmanii W. Smith
   NM (Elephant Butte Lake, Ute Lake)

Epithemia reichelti Fricke
   AZ (Rio Salado, Rio Verde)    NM (Elephant Butte Lake)

Epithemia sorex Kützing
   AZ (Lake Powell, Grand Canyon, Central Arizona Project, Southern Arizona Lakes, Oak Creek, Canyon Lake, Chevelon Creek, East Turkey Creek, Sycamore Creek, Tonto Creek, Cave Creek, Ayers Lake, East Verde River, Rio Salado, San Pedro River, Santa Cruz River, Gila River, Rio Verde, West Clear Creek) NM (State record, Railroad Canyon, Rio Chama, San Juan River, Elephant Butte Lake, Conchas Lake, Rio Grande, Rio Brazos, Charette Lake, Ute Lake, Santa Rosa Lake, Jemez River, Rito de Los Frijoles)

Epithemia turgida (Ehrenberg) Kützing
   SYN: Epithemia emarginata Andrews    AZ (Grand Canyon, Central Arizona Project, Southern Arizona Lake, Oak Creek, Chevelon Creek, East Turkey Creek, Rio Salado, San Pedro River)    NM (State Record, Railroad Canyon, Elephant Butte Lake, Conchas Lake, Rio Brazos, San Juan River, Rio Grande)    W TX (Shafter)

Epithemia turgida var. granulata (Ehrenberg) Brun
   AZ (West Clear Creek)

Epithemia turgida var. westermannii (Ehrenberg) Grunow
   AZ (Chevelon Creek)   NM (Rio Brazos)

Epithemia sp. 1 NAWQA
   AZ (Rio Verde, West Clear Creek, San Pedro River?)

Epithemia sp.
   W TX (Palo Pinto Canyon)

Eucocconeis flexella (Kützing) Meister
   SYN: Achnanthes flexella (Kützing) Brun    AZ (Lake Powell, Grand Canyon)

Eucocconeis laevis (Østrup) Lange-Bertalot in Lange-Bertalot & Genkal
   SYN: Achnanthes laevis Østrup    AZ (Rio Salado)

Eunotia arcus Ehrenberg
   AZ (Sheep's Crossing)

Eunotia bidentula W. Smith
   AZ (West Clear Creek)

Eunotia bilunaris (Ehrenberg) Mills
   SYN: Eunotia curvata (Kützing) Lagerstedt    AZ (Sheep's Crossing)

Eunotia bilunaris var. mucophila Lange-Bertalot & Norpel
   AZ (Big Lake Outlet)

Eunotia diodon Ehrenberg
   AZ (Sheep's Crossing)

Eunotia major (W. Smith) Rabenhorst
   AZ (Sheep's Crossing)

Eunotia muscicola var. tridentula Nörpel & Lange-Bertalot
   AZ (San Pedro River)

Eunotia pectinalis (Kützing) Rabenhorst
   SYN: Eunotia pectinalis var. ventricosa (Ehrenberg) Grunow in Van Heurck   AZ (Sheep's Crossing)

Eunotia pectinalis var. undulata (Ralfs) Rabenhorst
   NM (Rio Grande)

Eunotia rostellata Hustedt ex Patrick
   NM (Pecos River)

Eunotia sp.
   NM (Rattlesnake Spring)

Fallacia auriculata (Hustedt) D. Mann in Round et al.
   SYN: Navicula auriculata Hustedt    AZ (Canyon Lake, Rio Salado)

Fallacia dissipatoides (Hustedt) Metzeltin, Lange-Bertalot & Garcia- Rodriguez
   SYN: Navicula insociabilis var. dissipatoides Hustedt    NM (Conchas Lake, Elephant Butte Lake)

Fallacia helensis (Schulz) D. Mann in Round et al.
   SYN: Navicula helensis Schulz    AZ (San Pedro River, West Clear Creek)    NM (Conchas Lake)

Fallacia indifferens (Hustedt) D. Mann in Round et al.
   SYN: Navicula indifferens Hustedt    AZ (Cave Creek, Queen Creek)    NM (Railroad Canyon, Aguirre Springs)

Fallacia insociabilis (Krasske) D. Mann in Round et al.
   SYN: Navicula insociabilis Krasske    NM (Charette Lake)

Fallacia lenzii (Hustedt) Lange-Bertalot in Werum & Lange-Bertalot
   SYN: Navicula lenzii Hustedt    AZ (West Clear Creek)

Fallacia ochridana (Hustedt)Levkov & Krstic in Levkov et al.
   SYN: Navicula ochridana Hustedt    NM (Rio Chama, Rito de Los Frijoles, Santa Fe River, Red River, Rio Grande, Rio Pueblo de Taos)

Fallacia pygmaea (Kützing) Stickle & D. Mann in Round et al.
   SYN: Navicula pygmaea Kützing    AZ (Lake Powell, Chevelon Creek, San Pedro River)   NM (Conchas Lake, San Juan River, Rio Grande, Rio Chama)

Fallacia subhamulata (Grunow in Van Heurck) D. Mann in Round et al.
   SYN: Navicula subhamulata Grunow in Van Heurck    AZ (Canyon Lake, Chevelon Creek, Rio Verde, West Clear Creek)

Fistulifera pelliculosa (Brébisson) Lange Bertalot
   SYN: Navicula pelliculosa (Brébisson) Hilse    AZ (Grand Canyon, Canyon Lake, Chevelon Creek, San Pedro River, Rio Verde)    NM (Rio Chama, Rito de Los Frijoles, Santa Fe River, Rio Grande, Rio Pueblo de Taos)

Fragilaria capucina Desmazieres
   AZ (San Pedro River, West Clear Creek)

Fragilaria capucina var. amphicephala (Grunow) Lange-Bertalot
   NM (Conchas Lake)

Fragilaria crotonensis Kitton
   AZ (Hawley Lake, Crescent Lake, Big Lake)    NM (Elephant Butte Lake, Conchas Lake, Rio Brazos, Charette Lake, San Juan River, Ute Lake, Santa Rosa Lake, Rio Grande)

Fragilaria crotonensis var. oregona Sovereign
   NM (Conchas Lake)

Fragilaria gracilis Østrup
   SYN: Fragilaria capucina var. gracilis (Østrup) Hustedt    AZ (San Pedro River, West Clear Creek)

Fragilaria heidenii Østrup
   SYN: Fragilaria inflata (Heiden) Hustedt    NM (Rio Grande, Conchas Lake)

Fragilaria perminuta (Grunow) Lange-Bertalot in Krammer & Lange-Bertalot
   SYN: Fragilaria capucina var. perminuta (Grunow) Lange-Bertalot    AZ (West Clear Creek)

Fragilaria pinnata var. acuminata Mayer
   AZ (West Clear Creek) [If valid, this taxon should be formally moved to Staurosirella.]

Fragilaria vaucheriae (Kützing) Petersen
   SYN: Fragilaria vaucheriae var. distans (Grunow) Cleve-Euler    AZ (Oak Creek, Chevelon Creek, East Turkey Creek, Cave Creek, Rio Salado, East Verde River, San Pedro River, Gila River, Rio Verde, West Clear Creek)    NM (State record, Conchas Lake, Elephant Butte Lake, Heron Lake, Rio Grande, Rio Brazos, San Juan River, Ute Lake, Santa Rosa Lake, Rio Chama, Rio Chama, Embudo Creek, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos)

Fragilaria vaucheriae var. capitellata (Grunow in Van Heurck) R. Ross
   NM (Elephant Butte Lake)

Fragilaria sp. 1 NAWQA
   AZ (Rio Verde, Gila River)

Fragilariforma constricta (Ehrenberg) Williams & Round
   SYN: Fragilaria constricta Ehrenberg    NM (San Juan River)

Fragilariforma virescens (Ralfs) Williams & Round
   SYN: Fragilaria virescens Ralfs   NM (McAllister Lake, Charette Lake)

Fragilariforma virescens var. mesolepta (Rabenhorst) Andresen, Stoermer & Kreis
   SYN: Fragilaria mesolepta Rabenhorst, Fragilaria capucina var. mesolepta (Rabenhorst) Rabenhorst    AZ (Grand Canyon, Central Arizona Project, Southern Arizona Lakes, Upper Lake Mary, Chevelon Creek, Cave Creek, San Pedro River)    NM (Elephant Butte Lake, Rio Brazos, San Juan River, Rio Grande)

Fragilariforma virescens var. exigua (Grunow in Cleve & Möller) Poulin
   NM (Charette Lake)

Frustulia amphipleuroides (Grunow) A. Cleve
   SYN: Frustulia rhomboides var. amphipleuroides (Grunow) De Toni    AZ (Sheep's Crossing)   NM (Rito de Los Frijoles, Santa Fe River)

Frustulia cf. krammeri Lange-Bertalot & Metzeltin
   SYN: Frustulia rhomboides (Ehrenberg) De Toni    AZ (Sheep's Crossing)

Frustulia saxonica Rabenhorst
   SYN: Frustulia rhomboides var. saxonica (Rabenhorst) De Toni    NM (Santa Rosa Lake)

Frustulia cf. saxonica Rabenhorst
   SYN: Frustulia rhomboides var. saxonica (Rabenhorst) Pfitzer    AZ (Sheep's Crossing) [The valve outline and very fine striae reported by Czarnecki et al. make this identification rather unlikely. It seems more like F. gaertneri, but that species has not been reported from North America.]

Frustulia vulgaris (Thwaites) De Toni
   AZ (Big Lake Outlet, East Verde River, Cave Creek, San Pedro River, West Clear Creek)    NM (Railroad Canyon, Rio Grande, Rio Brazos, Ute Lake, Santa Rosa Lake, Rio Chama, Rito de Los Frijoles, Rio Pueblo de Taos)

G-H

Geissleria acceptata (Hustedt) Lange-Bertalot & Metzeltin
   SYN: Navicula acceptata Hustedt    AZ (West Clear Creek)

Geissleria decussis (Østrup) Lange Bertalot & Metzeltin
   SYN: Navicula decussis Østrup    AZ (Grand Canyon, Central Arizona Project, Chevelon Creek, Sycamore Creek, East Verde River, Cave Creek, Rio Verde, Canyon Lake, San Pedro River, West Clear Creek, Rio Salado, Santa Cruz River)    NM (Rio Grande, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River)

Geissleria schoenfeldii (Østrup) (Hustedt) Lange-Bertalot & Metzeltin
   SYN: Navicula schoenfeldii Hustedt    AZ (West Clear Creek)    NM (Rito de Los Frijoles)

Gomphoneis eriense (Grunow) Skvortzow & Meyer
   NM (Elephant Butte Lake, Rio de los Peños, Conchas Lake, Rio Grande, Rio Chama)

Gomphoneis herculeana (Ehrenberg) Cleve
   AZ (Chevelon Creek, Oak Creek)    NM (Rio de los Peñs, Rio Brazos, San Juan River, Rio Grande)

Gomphoneis herculeana var. robusta (Grunow) Cleve
   AZ (Sheep's Crossing)    NM (Conchas Lake, Rio Brazos?, Santa Rosa Lake, Rio Grande)

Gomphoneis heterominuta Mayama & Kawashima in Mayama et al.
   SYN: Gomphonema minutum (Agardh) Agardh    AZ (San Pedro River, Gila River, Santa Cruz River, Rio Verde, West Clear Creek)

Gomphoneis olivacea (Hornemann) Dawson ex Ross & Sims
   SYN: Gomphonema olivaceum (Lyngbye) Kützing    AZ (Grand Canyon, Central Arizona Project, Southern Arizona Lakes, Upper Lake Mary, Canyon Lake, East Verde River, Cave Creek, San Pedro River, Rio Salado, Santa Cruz River, Gila River, Rio Verde, West Clear Creek)    NM (Rio Chama, Elephant Butte Lake, Conchas Lake, Rio Grande, Charette Lake, San Juan River, Ute Lake, Embudo Creek, Rio Chama, Jemez River, Santa Fe River, Rio Pueblo de Taos)

Gomphoneis olivacea var. calcarea (Cleve) Hartley
   SYN: Gomphonema olivaceum var. calcarea (Cleve) Cleve    NM (Elephant Butte Lake, Conchas Lake, San Juan River, Ute Lake)

Gomphoneis olivaceoides (Hustedt) Carter in Carter & Bailey-Watts
   SYN: Gomphonema olivaceoides Hustedt    NM (Rio Chama)

Gomphoneis rhombicum (Fricke) Merino et al.
   SYN: Gomphonema rhombicum Fricke in Schmidt    NM (Rito de Los Frijoles)

Gomphoneis septa (Moghadam) Kociolek, Stoermer & Bahls
   SYN: Gomphonema septum Moghadam    NM (Ute Lake)

Gomphonema abbreviatum Agardh
   NM (Rito de Los Frijoles)

Gomphonema acuminatum Ehrenberg
   AZ (Big Lake Outlet, Grand Canyon, Oak Creek, East Turkey Creek, Sycamore Creek, Tonto Creek, Cave Creek, Crescent Lake, West Clear Creek)    NM (Railroad Canyon, Conchas Lake, Rio Brazos, San Juan River, Santa Rosa Lake)

Gomphonema affine Kützing
   AZ (Chevelon Creek, San Pedro River, Rio Verde, West Clear Creek)    NM (Conchas Lake, McAllister Lake, Rio Grande)

Gomphonema cf. affine Kützing
   W TX (Palo Pinto Canyon)

Gomphonema affine var. insignis (Gregory) Andrews
   AZ (Grand Canyon, San Pedro River, West Clear Creek)

Gomphonema angustatum (Kützing) Rabenhorst
   AZ (Oak Creek, San Pedro River, Rio Salado, Gila River, West Clear Creek)    NM (Rio Grande, Rio Brazos, San Juan River, Rito de Los Frijoles)

Gomphonema angustatum var. citera (Hohn & Hellerman) Patrick
  NM (Conchas Lake, Rio Grande)

Gomphonema angustatum var. intermedia Grunow in Van Heurck
  NM (Rio Chama, Rio Grande)

Gomphonema apicatum Ehrenberg
   NM (Conchas Lake)

Gomphonema brasiliense Grunow
   NM (Rio Chama)

Gomphonema brebissonii Kützing
   AZ (Sheep's Crossing)

Gomphonema clavatum Ehrenberg
   AZ (San Pedro River)    NM (Rio Brazos)

Gomphonema cf. clavatum UMICH
   AZ (West Clear Creek)

Gomphonema clevei Fricke
   NM (Rio Grande, Rio Brazos, San Juan River, Embudo Creek, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos)

Gomphonema dichotomum Kützing
   SYN: Gomphonema intricatum Kützing    AZ (Southern Arizona Lakes)    NM (Conchas Lake, Santa Rosa Lake)

Gomphonema exilissimum Lange-Bertalot & Reichardt
   SYN: Gomphonema parvulum var. exilissima Grunow in Van Heurck    AZ (Rio Salado, Santa Cruz River)

Gomphonema gracile Ehrenberg
   AZ (Southern Arizona Lakes, Oak Creek, Chevelon Creek, San Pedro River, West Clear Creek)    NM (Elephant Butte Lake, Rio Grande, Rio Brazos, San Juan River)    W TX (Laguna Prieta)

Gomphonema grunowii Patrick & Reimer
   SYN: Gomphonema lanceolatum Ehrenberg    AZ (Grand Canyon, Central Arizona Project, Oak Creek)    NM (Elephant Butte Lake, Rio Brazos, Rio Grande)

Gomphonema kobayasii Kociolek & Kingston
   AZ (San Pedro River, West Clear Creek)

Gomphonema longiceps Ehrenberg
   AZ (Southern Arizona Lakes)

Gomphonema longiceps var. subclavatum Grunow
   AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Tonto Creek)

Gomphonema mexicanum var. subclavatum Grunow in Van Heurck
   AZ (Rio Verde)

Gomphonema cf. mexicanum CALACAD
   AZ (San Pedro River)

Gomphonema montezumense Czarnecki & Blinn
   AZ (Montezuma Well)

Gomphonema olivaceum var. olivaceolacuum Lange-Bertalot & Reichardt
   NM (Charette Lake) [This taxon has not been formally moved to Gomphoneis.]

Gomphonema parvulum (Kützing) Kützing
   SYN: Gomphonema parvulum var. lagenula (Kützing) Frenguelli, Gomphonema parvulum var. micropus (Kützing) Cleve    AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Upper Lake Mary, Oak Creek, Chevelon Creek, East Turkey Creek, Tonto Creek, Queen Creek, Rio Salado, San Pedro River, 91st Avenue WWTP, Santa Cruz River, Gila River, Rio Verde, West Clear Creek)    NM (Rio Chama, Railroad Canyon, Elephant Butte Lake, Conchas Lake, McAllister Lake, Rio Grande, Rio Brazos, San Juan River, Santa Rosa Lake, Pecos River, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos)    W TX (Palo Pinto Canyon)

Gomphonema parvulum form saprophilumLange-Bertalot & Reichardt
   W TX (Laguna Preita)

Gomphonema productum Lange Bertalot & Reichardt in Lange Bertalot
   AZ (Southern Arizona Lakes)    NM (Pecos River)

Gomphonema pseudotenellum Lange-Bertalot
   SYN: Gomphonema tenellum Kützing    NM (Rio Grande, San Juan River?)

Gomphonema pumilum (Grunow) Reichardt & Lange-Bertalot
   AZ (Santa Cruz River, San Pedro River, Rio Verde, West Clear Creek)

Gomphonema pumilum var. rigidum Reichardt & Lange-Bertalot
   AZ (West Clear Creek)

Gomphonema subclavatum (Grunow) Grunow
   NM (San Juan River, Jemez River, Rito de Los Frijoles, Red River)

Gomphonema subclavatum var. commutatum (Grunow) Mayer
   NM (Rio Chama)

Gomphonema subclavatum var. mexicanum (Grunow) R.M.Patrick
   NM (Elephant Butte Lake, Conchas Lake) [This name was invalidly published, and should be replaced or validated.]

Gomphonema subtile Ehrenberg
   AZ (Hawley Lake)

Gomphonema tergestinum (Grunow) Fricke
   NM (Elephant Butte Lake, Conchas Lake?)

Gomphonema truncatum Ehrenberg
   AZ (Big Lake Outlet, Grand Canyon, Oak Creek, Tonto Creek, Cave Creek, Rio Verde, Rio Salado, East Verde River, San Pedro River, West Clear Creek)    NM (State Record, Carlito Spring, Railroad Canyon, Elephant Butte Lake, Conchas Lake, Rio Grande, Rio Brazos, Charette Lake, San Juan River, Santa Rosa Lake, Rio Chama, Red River, Rio Pueblo de Taos)

Gomphonema truncatum var. capitatum (Ehrenberg) Patrick in Patrick & Reimer
   AZ (Oak Creek, Cave Creek, Queen Creek)   NM (Elephant Butte Lake, Rio Brazos, San Juan River, Rio Grande)

Gomphonema truncatum var. turgidum (Ehrenberg) Patrick
   NM (Elephant Butte Lake)

Gomphonema ventricosum Gregory
   AZ (Oak Creek)    NM (Rio Grande, Rio Brazos)

Gomphonema vibrio var. intricatum (Kützing) R. Ross in Hartley
   AZ (Grand Canyon, Southern Arizona Lakes, Rio Verde)   NM (Rito de Los Frijoles)

Gomphonema vibrioides Reichardt & Lange Bertalot
   SYN: Gomphonema intricatum var. vibrio (Ehrenberg) Cleve    AZ (Grand Canyon)

Gomphosphenia grovei var. lingulata (Hustedt) Lange-Bertalot
   AZ (San Pedro River)

Gyrosigma acuminatum (Kützing) Rabenhorst
   SYN: Gyrosigma spencerii (W. Smith) Griffith & Henfrey    AZ (Lake Powell, Grand Canyon, Central Arizona Project, Upper Lake Mary, Canyon Lake, Chevelon Creek)    NM (Rio Grande, Charette Lake, Santa Rosa Lake, Conchas Lake, Rio Pueblo de Taos)

Gyrosigma attenuatum (Kützing) Rabenhorst
   AZ (Canyon Lake, Saguaro Lake, Rio Salado, San Pedro River)

Gyrosigma eximium (Thwaites) Boyer
   NM (Rio Grande)

Gyrosigma nodiferum (Grunow) Reimer
   AZ (San Pedro River, Rio Verde, West Clear Creek)

Gyrosigma obtusatum (Sullivant & Wormley) Boyer
   SYN: Gyrosigma scalproides (Rabenhorst) Cleve    AZ (East Verde River, San Pedro River)    NM (Conchas Lake, Charette Lake, Elephant Butte Lake, Conchas Lake, Ute Lake, Rio Grande)

Gyrosigma sciotoense (Sullivant & Wormley) Cleve
   NM (Elephant Butte Lake, Ute Lake)

Gyrosigma spencerii var. curvula (Grunow) Reimer
   AZ (Lake Powell, Grand Canyon, Chevelon Creek)    NM (Rio Brazos) [This name is illegitimate. The taxon needs a new name.]

Gyrosigma wansbeckii (Donkin) Cleve
   NM (McAllister Lake)

Halamphora acutiuscula (Kützing) Levkov
   SYN: Amphora acutiuscula Kützing    AZ (Chevelon Creek)    NM (Conchas Lake, Elephant Butte Lake)    W TX (Diamond Y Spring)

Halamphora coffeaeformis (Agardh) Levkov
   SYN: Amphora coffeaeformis (Agardh) Kützing    AZ (Lake Powell, Grand Canyon, Cholla Lake, Chevelon Creek)    NM (Conchas Lake, McAllister Lake)

Halamphora holsatica (Hustedt) Levkov
   SYN: Amphora holsatica Hustedt Patrick    AZ (Rio Salado, Rio Verde)

Halamphora montana (Krasske) Levkov
   AZ (Cave Creek, San Pedro River, 91st Avenue WWTP, Santa Cruz River, West Clear Creek)

Halamphora subcapitata (Kisselev) Levkov
   AZ (Rio Salado)

Halamphora submontana (Hustedt) Levkov
   SYN: Amphora submontana Hustedt    NM (Conchas Lake, Rio Grande)

Halamphora veneta (Kützing) Levkov
   SYN: Amphora veneta Kützing    AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Chevelon Creek, Seven Springs Wash, Cave Creek, Ayers Lake, Queen Creek, Rio Salado, San Pedro River, Gila River, Rio Verde)    NM (Conchas Lake, McAllister Lake, Rio Grande, Aguirre Springs, Santa Fe River)

Hannaea arcus (Ehrenberg) Patrick
   AZ (Oak Creek)    NM (Conchas Lake, Pecos River, Rio Grande, Rio Brazos, Santa Fe River, Red River, Rio Pueblo de Taos)

Hannaea arcus var. amphioxys (Rabenhorst) Patrick
   NM (San Juan River, Embudo Creek, Red River, Rio Pueblo de Taos)

Hantzschia amphioxys (Ehrenberg) Grunow
   AZ (Lake Powell, Grand Canyon, Central Arizona Project, Canyon Lake, Chevelon Creek, Big Lake Outlet, East Verde River, Cave Creek, Sunrise Lake, Ayers Lake, Queen Creek)    NM (Laguna Larga, Conchas Lake, McAllister Lake, Rio Grande, Rio Brazos, Charette Lake, San Juan River, Ute Lake, Santa Rosa Lake, Aguirre Springs, Embudo Creek, Rio Chama, Rito de Los Frijoles, Santa Fe River, Rio Grande)    W TX (Laguna Prieta)

Hantzschia amphioxys var. capitata O. Müller
   NM (McAllister Lake)    W TX (Palo Pinto Canyon)

Hantzschia spectabilis (Ehrenberg) Hustedt
   AZ (Chevelon Creek) [Listed in Czarnecki et al. as Nitzschia vivax W. Smith, the basionym of Hantzschia vivax (W. Smith) Peragallo. Their illustration, however, looks much more like the present species, a synonym of which is Nitzschia vivax Hantzsch. Perhaps a mistake in nomenclature?]

Hantzschia virgata (Roper) Grunow in Cleve & Grunow
   AZ (Chevelon Creek)   NM (McAllister Lake? Rio Grande)

Hippodonta capitata (Ehrenberg) Lange Bertalot, Metzeltin & Witkowski
   SYN: Navicula capitata Ehrenberg    AZ (Lake Powell, Chevelon Creek, Bartlett Lake, East Verde River, San Pedro River, Rio Salado, Gila River, Rio Verde)    NM (Elephant Butte Lake, Rio Chama, Rio Grande, Rio Brazos, Charette Lake, San Juan River, Jemez River, Santa Fe River)

Hippodonta hungarica (Grunow) Lange Bertalot, Metzeltin & Witkowski
   SYN: Navicula capitata var. hungarica (Grunow) Ross    AZ (Lake Powell, Southern Arizona Lakes, San Pedro River, Bartlett Lake)    NM (Conchas Lake, McAllister Lake, Charette Lake, Ute Lake, Rio Grande)

Hippodonta lueneburgensis (Grunow) Lange Bertalot, Metzeltin & Witkowski
   SYN: Navicula capitata var. lueneburgensis (Grunow) Patrick    NM (Conchas Lake)

K-L-M-N

Karayevia amoena (Hustedt) Bukhtiyarova
   SYN: Achnanthes amoena Hustedt    AZ (San Pedro River, Santa Cruz River, West Clear Creek)

Karayevia clevei (Grunow in Cleve & Grunow) Round & Bukhtiyarova
   SYN: Achnanthes clevei Grunow in Cleve & Grunow    AZ (Grand Canyon, Rio Verde, Rio Salado, San Pedro River, 91st Avenue WWTP, Gila River, Santa Cruz River, West Clear Creek)   NM (Rito de Los Frijoles)

Karayevia clevei var. rostrata (Hustedt) Bukhtiyarova
   SYN: Achnanthes clevei var. rostrata Hustedt    AZ (Sheep's Crossing)

Karayevia laterostrata (Hustedt) Round & Bukhtiyarova
   SYN: Achnanthes laterostrata Hustedt    AZ (Lake Powell, West Clear Creek)

Kobayasiella subtilissima (Cleve) Lange Bertalot
   SYN: Navicula subtilissima Cleve    AZ (Grand Canyon)    NM (Conchas Lake, Santa Rosa Lake, Rio Grande)

Kolbesia gessneri (Hustedt) Aboal in Aboal et al.
   SYN: Achnanthes gessneri Hustedt    AZ (Rio Verde)

Lemnicola hungarica (Grunow) Round & Basson
   SYN: Achnanthes hungarica (Grunow) Grunow    AZ (Chevelon Creek, Sheep's Crossing, Rio Salado, Santa Cruz River)

Luticola cohnii (Hilse) D. Mann in Round et al.
   SYN: Navicula cohnii (Hilse) Lange-Bertalot    AZ (Grand Canyon, San Pedro River)    NM (Santa Rosa Lake, Aguirre Springs, Rio Chama, Rito de Los Frijoles, Santa Fe River, Rio Grande)

Luticola mutica (Kützing) D. Mann in Round et al.
   SYN: Navicula mutica Kützing.    AZ (Grand Canyon, Chevelon Creek, Big Lake Outlet, Cave Creek, Ayers Lake, Queen Creek, Rio Salado, East Verde River, San Pedro River, West Clear Creek, Gila River, Santa Cruz River, Rio Verde)    NM (Rio Brazos, Rio Grande)

Luticola mutica var. ventricosa (Kützing) Hamilton in Hamilton et al.
   SYN: Luticola ventricosa (Kützing) D. Mann in Round et al.    AZ (San Pedro River, Gila River)

Luticola paramutica (Bock) D. Mann in Round et al.
   SYN: Navicula paramutica Bock    AZ (San Pedro River)

Luticola stigma (Patrick) Johansen in Johansen et al.
   AZ (Grand Canyon, Rio Verde)

Luticola undulata (Hilse in Rabenhorst) D. Mann in Round et al.
   AZ (Grand Canyon)

Luticola n. sp. A
   W TX (Ft. Davis CDRI)

Martyana schulzii (Brockmann) Snoeijs in Snoeijs et al.
   SYN: Fragilaria schulzii Brockmann, Opephora schulzii (Brockmann) Simonsen    AZ (Chevelon Creek)[Since Opephora martyi, the generotype of Martyana, has been moved to Staurosirella, this taxon presumably belongs there as well]

Mastogloia braunii Grunow
   AZ (Chevelon Creek)    W TX (Diamond Y Spring)

Mastogloia braunii var. pumila Cleve Euler
   AZ (Chevelon Creek)

Mastogloia elliptica (Agardh) Cleve in Schmidt et al.
   NM (Conchas Lake, Charette Lake, Ute Lake, Rio Chama)    AZ (Rio Verde, West Clear Creek, San Pedro River?)

Mastogloia elliptica var. dansei (Thwaites) Cleve
   AZ (Lake Powell, Grand Canyon, Chevelon Creek)    NM (Elephant Butte Lake, Charette Lake)    W TX (Diamond Y Spring, Palo Pinto Canyon)

Mastogloia grevillei W. Smith
   AZ (Grand Canyon)

Mastogloia smithii Thwaites ex W. Smith
   AZ (Lake Powell, Grand Canyon, Chevelon Creek, Canyon Lake, San Pedro River, Rio Salado, Rio Verde)    NM (Conchas Lake, McAllister Lake, Cochiti Lake, Ute Lake, Santa Rosa Lake)

Mastogloia smithii var. amphicephala Grunow in Van Heurck
   AZ (Grand Canyon)    NM (State record)

Mastogloia smithii var. lacustris Grunow
   AZ (Lake Powell, Grand Canyon, Central Arizona Project, Chevelon Creek)    NM (Conchas Lake, Ute Lake)

Mastogloia sp. 1 NAWQA
   AZ (Rio Verde)

Mayamaea agrestis (Hustedt) Lange-Bertalot
   SYN: Navicula agrestis Hustedt    AZ (San Pedro River,Rio Verde)

Mayamaea atomus (Kützing) Lange-Bertalot
   SYN: Navicula atomus Kützing    AZ (West Clear Creek, San Pedro River, 91st Avenue WWTP, Santa Cruz River)

Melosira lineata (Dillwyn) Agardh
   AZ (West Clear Creek    NM (Rio Chama, Elephant Butte Lake, Conchas Lake, Rio Grande, Rio Brazos, San Juan River, Santa Rosa Lake)

Melosira undulata (Ehrenberg) Kützing
   NM (Santa Rosa Lake)

Melosira varians Agardh
   AZ (Grand Canyon, Southern Arizona Lakes, Central Arizona Project, Upper Lake Mary, Canyon Lake, Chevelon Creek, East Turkey Creek, Sycamore Creek, East Verde River, Cave Creek, Oak Creek, Queen Creek, Bartlett Lake, Rio Verde, Rio Salado, San Pedro River, Gila River, West Clear Creek)    NM (San Juan River, Railroad Canyon, Conchas Lake, Rio Brazos, Ute Lake, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Grande)

Meridion anceps (Ehrenberg) D. Williams
   SYN: Diatoma anceps (Ehrenberg) Kirchner    NM (Lobo Creek, Conchas Lake, Pecos River, Rio Brazos, Santa Fe River, Red River)

Meridion circulare (Greville) Agardh
   AZ (Oak Creek, Sycamore Creek, East Verde River, Cave Creek, Queen Creek, San Pedro River, West Clear Creek)    NM (Pecos River, Rio Grande, Rio Brazos, Ute Lake, Aguirre Springs, Rito de Los Frijoles, Santa Fe River, Red River)

Meridion circulare var. constrictum (Ralfs) Van Heurck
   AZ (Chevelon Creek, East Turkey Creek, Big Lake Outlet, Tonto Creek, Oak Creek, Queen Creek, Sheep's Crossing)    NM (San Juan River)

Navicula anglica var. subsalsa (Grunow) Cleve
   AZ (Chevelon Creek)    [It seems that this taxon has not been formally tranferred to Placoneis. Placoneis subsalsa Mereschkowsky might have been based on the Grunow basionym. Navicula anglica Ralfs in Pritchard clearly belongs in Placoneis, see below.]

Navicula angusta Grunow
   AZ (San Pedro River, Rio Salado, 91st Avenue WWTP, West Clear Creek)

Navicula antonii Lange-Bertalot in Rumrich et al.
   AZ (San Pedro River, West Clear Creek)

Navicula arvensis Hustedt
   AZ (Grand Canyon, Oak Creek, San Pedro River, Santa Cruz River, West Clear Creek)    NM (Rio Grande, Rio Brazos, San Juan River, Rio Chama, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos)

Navicula bicornica Patrick
   NM (Rio Chama, Santa Fe River, Rio Grande)

Navicula brevissima Hustedt
   NM (McAllister Lake)

Navicula canalis Patrick
   AZ (San Pedro River)    NM (Rio Grande, Jemez River)

Navicula capitatoradiata Germain
   SYN: Navicula salinarum var. intermedia (Grunow in Van Heurck) Cleve    AZ (Central Arizona Project, Southern Arizona Lakes, Rio Verde, East Verde River, Tonto Creek, Tonto Creek, San Pedro River, Gila River, West Clear Creek, Bartlett Lake)    NM (Rio Grande, Santa Rosa Lake, Rio Chama, Railroad Canyon, Embudo Creek, Jemez River, Rito de Los Frijoles, Rio Pueblo de Taos)

Navicula cari Ehrenberg
  AZ (Santa Cruz River, Verde River) NM (McAllister Lake, Rio Chama, Rito de Los Frijoles, Santa Fe River, Rio Grande, Rio Publo de Taos, Red River)

Navicula caterva Hohn & Hellerman
   AZ (West Clear Creek)

Navicula cincta (Ehrenberg) Ralfs in Pritchard
   SYN: Navicula heufleri Grunow    AZ (Lake Powell, Grand Canyon, Canyon Lake, Chevelon Creek, , Rio Verde, San Pedro River, West Clear Creek)   NM (Rio Chama, Santa Fe River, Red River, Rio Grande)

Navicula convergens Patrick
   NM (Rio Chama, Rito de Los Frijoles, Santa Fe River, Rio Grande)

Navicula cryptocephala Kützing
   AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Upper Lake Mary, Oak Creek, Canyon Lake, Chevelon Creek, San Pedro River, Rio Salado, Gila River, Rio Verde, West Clear Creek)    NM (Conchas Lake, San Juan River, Elephant Butte Lake, McAllister Lake, Rio Brazos, Charette Lake, Cochiti Lake, Santa Rosa Lake, Rio Chama, Santa Fe River, Rio Grande, Rio Pueblo de Taos)

Navicula cryptocephala f. minuta Petersen
   AZ (Grand Canyon, Chevelon Creek)

Navicula cryptotenella Lange-Bertalot in Krammer & Lange-Bertalot
   SYN: Navicula radiosa var. tenella (Brébisson in Kützing) Cleve & Möller    AZ (Lake Powell, Grand Canyon, Chevelon Creek, San Pedro River, Rio Salado, 91st Avenue WWTP, Santa Cruz River, Gila River, Rio Verde, West Clear Creek)    NM (Rio Chama, Rio Brazos, Rio Grande, San Juan River, Santa Rosa Lake)

Navicula cryptotenelloides Lange-Bertalot
   AZ (West Clear Creek)

Navicula difficillima Hustedt
   AZ (San Pedro River)

Navicula erifuga Lange-Bertalot in Krammer & Lange-Bertalot
   SYN: Navicula heufleri var. leptocephala (Brebisson ex Grunow) Patrick    AZ (Chevelon Creek, San Pedro River, West Clear Creek)    NM (Rio Brazos)    W TX (Palo Pinto Canyon)

Navicula exigua var. capitata Patrick
   NM (Conchas Lake, Elephant Butte Lake, Rio Grande, Rio Brazos, Rito de Los Frijoles, Santa Fe River) [Navicula exigua (Gregory) Grunow in Van Heurck is now Placoneis elginensis f. exigua (Gregory) Bukhtiyarova. If this variety is valid, then it also belongs in Placoneis.]

Navicula exilis Kützing
   SYN: Navicula cryptocephala var. exilis Grunow in Van Heurck    AZ (San Pedro River, Rio Salado, 91st Avenue WWTP, Santa Cruz River, Gila River, Rio Verde)    NM (Elephant Butte Lake, McAllister Lake, Rio Chama, Rio Grande)

Navicula festiva Krasske
   NM (Conchas Lake)

Navicula genovefae Fusey
   NM (Rito de Los Frijoles, Santa Fe River, Rio Grande)

Navicula germainii Wallace
   SYN: Navicula rhynchocephala var. germainii (Wallace) Patrick, Navicula viridula var. germainii (Wallace) Lange-Bertalot    AZ (San Pedro River, Gila River)    NM (McAllister Lake, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Rio Grande, Rio Pueblo de Taos)

Navicula gottlandica Grunow in Van Heurck
   NM (Rio Grande)

Navicula graciloides Mayer
   AZ (Lake Powell, Southern Arizona Lakes, Chevelon Creek)

Navicula gregaria Donkin
   AZ (Lake Powell, Grand Canyon, Chevelon Creek, San Pedro River, Rio Salado, 91st Avenue WWTP, Gila River, Santa Cruz River, Rio Verde, West Clear Creek)    NM (Rio Chama, Santa Fe River, Red River, Rio Grande)

Navicula grimmei Krasske in Hustedt
   AZ (Grand Canyon)

Navicula harderi Hustedt in Brendemühl
   AZ (San Pedro River)

Navicula inflexa (Gregory) Ralfs in Pritchard
   AZ (Chevelon Creek)

Navicula ingenua Hustedt
   AZ (San Pedro River)

Navicula kotschyi Grunow
   AZ (San Pedro River)    NM (Conchas Lake, Elephant Butte Lake)

Navicula lanceolata (Agardh) Kützing
   SYN: Navicula avenacea (Brébisson & Godey) Brébisson ex Grunow, Navicula viridula var. avenacea (Brébisson) Van Heurck    AZ (Grand Canyon, Southern Arizona Lakes, Chevelon Creek, West Clear Creek, Gila River, Rio Verde)  NM (Embudo Creek, Rito de Los Frijoles, Santa Fe River, Rio Grande, Rio Chama, Rio Pueblo de Taos)

Navicula libonensis Schoeman
   AZ (San Pedro River, Rio Verde, West Clear Creek)

Navicula medioconvexa Hustedt
   AZ (West Clear Creek)

Navicula menisculus Schumann
   AZ (San Pedro River, West Clear Creek)    NM (Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Rio Grande)

Navicula meniscus Schumann
   AZ (San Pedro River, Rio Salado, Gila River, Santa Cruz River, Rio Verde, West Clear Creek)

Navicula mournei Patrick
   NM (Rio Brazos)

Navicula mutica var. tropica Hustedt
   NM (Rio Grande, Rio Brazos) [This taxon should be formally moved to Luticola.]

Navicula notha Wallace
   AZ (Lake Powell, Grand Canyon, San Pedro River, Rio Salado, Santa Cruz River, Rio Verde, West Clear Creek)    NM (McAllister Lake)

Navicula nuwukiana Patrick & Freese
   AZ (91st Avenue WWTP)

Navicula oblonga (Kützing) Kützing
   AZ (Central Arizona Project)    NM (Conchas Lake, Ute Lake)    W TX (Ft. Davis CDRI, Shafter)

Navicula obsoleta Hustedt
   AZ (91st Avenue WWTP)

Navicula odiosa Wallace
   AZ (Lake Powell)    NM (Rio Brazos)

Navicula omissa Hustedt
   NM (Rio Grande)

Navicula paratunkae Petersen
   NM (Rio Grande)

Navicula paucivisitata Patrick
   NM (Embudo Creek, Rio Chama, Rito de Los Frijoles, Santa Fe River, Rio Grande) [This species probably belongs in the genus Craticula, possibly as a synonym of C. molestiformis.]

Navicula peregrina (Ehrenberg) Kützing
   AZ (Chevelon Creek)   NM (Rio Grande)

Navicula peregrina var. oblonga Østrup
   SYN: Navicula oblonga Østrup (invalid)    AZ (San Pedro River)

Navicula perminuta Grunow in Van Heurck
   SYN: Navicula cryptocephala var. perminuta (Grunow in Van Heurck) Cleve   AZ (San Pedro River)    NM (Elephant Butte Lake)

Navicula phyllepta Kützing
   AZ (San Pedro River, West Clear Creek)

Navicula pseudolanceolata Lange-Bertalot
   AZ (Rio Verde)

Navicula pseudoreinhardtii Patrick
   AZ (Grand Canyon)

Navicula radiosa Kützing
   AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Upper Lake Mary, Chevelon Creek, East Turkey Creek, Cave Creek, Rio Verde, Canyon Lake, San Pedro River, Gila River, Santa Cruz River, West Clear Creek)    NM (Rio Chama, Railroad Canyon, Elephant Butte Lake, Conchas Lake, Rio Brazos, Ute Lake, Santa Rosa Lake, , Rito de Los Frijoles, Red River, Rio Grande)

Navicula radiosafallax Lange-Bertalot
   AZ (San Pedro River, West Clear Creek )

Navicula reichardtiana Lange-Bertalot in Lange-Bertalot & Krammer
   AZ (West Clear Creek, Bartlett Lake)

Navicula rhynchocephala Kützing
   AZ (Lake Powell, Central Arizona Project, Rio Salado, Rio Verde, West Clear Creek)    NM (Rio Grande, Rio Brazos, Ute Lake, Santa Fe River)

Navicula rhynchotella Lange-Bertalot
   SYN: Navicula rhynchocephala var. amphiceros (Kützing) Grunow    NM (Conchas Lake, Rio Grande, Rio Brazos, Santa Rosa Lake)

Navicula romana (Rabenhorst) Ralfs in Pritchard
   NM (Conchas Lake)

Navicula rostellata Kützing
   SYN: Navicula viridula var. rostellata (Kützing) Cleve    AZ (Lake Powell, Grand Canyon, Chevelon Creek, Cave Creek, San Pedro River, West Clear Creek, Rio Salado, Gila River, Santa Cruz River, Rio Verde)    NM (Rio Brazos, Jemez River)

Navicula salinarum Grunow
   AZ (Oak Creek, Canyon Lake, Gila River, Rio Verde)

Navicula sanctaecrucis Østrup
   NM (Rio Grande)

Navicula schroeteri Meister
   SYN: Navicula schroeteri var. escambia Patrick   AZ (San Pedro River, 91st Avenue WWTP, Santa Cruz River, Rio Verde, West Clear Creek)

Navicula secreta var. apiculata Patrick
   AZ (Grand Canyon, Southern Arizona Lakes, Chevelon Creek)  ) NM (Rio Chama, Jemez River, Santa Fe River, Red River, Rio Grande, Rio Pueblo de Taos)

Navicula seminuloides Hustedt
   AZ (San Pedro River)

Navicula subfasciata Patrick
   AZ (Upper Lake Mary) [This name seems to be a homonym of Navicula subfasciata Pantocsek, which has priority.]

Navicula subhamulata var. undulata Hustedt
   NM (Conchas Lake) [The nominate N. subhamulata has been transferred to Fallacia, but this variety has not been formally moved.]

Navicula subinflatoides Hustedt
   AZ (Chevelon Creek)

Navicula subrhynchocephala Hustedt
   AZ (Rio Salado)

Navicula symmetrica Patrick
   SYN: Navicula schroeteri var. symmetrica (Patrick) Lange-Bertalot   AZ (San Pedro River, Gila River, West Clear Creek)   NM (Rio Chama, Rio Grande)

Navicula tenelloides Hustedt
   AZ(Lake Powell, Chevelon Creek, San Pedro River, Rio Salado, 91st Avenue WWTP, Gila River, Rio Verde, West Clear Creek)

Navicula tridentula Krasske
   AZ (Grand Canyon, West Clear Creek)

Navicula tripunctata (O. F. Müller) Bory
   SYN: Navicula gracilis Ehrenberg, Navicula gracilis var. neglecta (Thwaites) Grunow in Van Heurck    AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Oak Creek, Canyon Lake, Chevelon Creek, East Verde River, Cave Creek, San Pedro River, Rio Salado, 91st Avenue WWTP, Santa Cruz River, Gila River, Rio Verde, West Clear Creek)    NM (State record, San Juan River, Rio Chama, Conchas Lake, Elephant Butte Lake, Pecos River, Rio Grande, Rio Brazos, Charette Lake, Ute Lake, Santa Rosa Lake, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos)

Navicula tripunctata var. schizonemoides (Van Heurck) Patrick
   AZ (Grand Canyon, Chevelon Creek, Oak Creek, Rio Verde, San Pedro River)    NM (Elephant Butte Lake, Rio Chama, Rio Grande, San Juan River, Jemez River, Santa Fe River) [Lange-Bertalot suggests that this form is more likely to be conspecific with Navicula recens (Lange-Bertalot) Lange-Bertalot.]

Navicula trivialis Lange-Bertalot
   AZ (San Pedro River, West Clear Creek)

Navicula upsaliensis (Grunow) Peragallo
   SYN: Navicula menisculus var. upsaliensis Grunow in Van Heurck    AZ (Sheep's Crossing, Rio Verde, West Clear Creek)

Navicula venerablis Hohn & Hellerman
   AZ (East Verde River)

Navicula veneta Kützing
   SYN: Navicula cryptocephala var. veneta (Kützing) Rabenhorst, Navicula cryptocephala var. subsalina Hustedt    AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Chevelon Creek, 91st Avenue WWTP, Rio Verde, Santa Cruz River, San Pedro River, West Clear Creek)    NM (McAllister Lake, Elephant Butte Lake, Rio Brazos, Ute Lake, Embudo Creek, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Rio Grande, Rio Pueblo de Taos)

Navicula viridula (Kützing) Ehrenberg
   AZ (Lake Powell, Grand Canyon, Chevelon Creek, San Pedro River, Gila River, West Clear Creek)    NM (Rio Grande, San Juan River)

Navicula viridula var. linearis Hustedt
   AZ (Upper Lake Mary)    NM (Elephant Butte Lake, Rio Grande, Rio Brazos)

Navicula vulpina Kützing
   SYN: Navicula viridula var. vulpina (Kützing) Lange-Bertalot    AZ (Central Arizona Project, Chevelon Creek)

Navicula zanonii Hustedt
   AZ (Lake Powell, Grand Canyon)

Neidium affine (Ehrenberg) Pfitzer
   AZ (Sheep's Crossing, San Pedro River)    NM (Pecos River, Rio Brazos)

Neidium affine var. amphirhynchus (Ehrenberg) Cleve
   NM (Pecos River)

Neidium affine var. humerus Reimer
   AZ (Sheep's Crossing)

Neidium amphigomphus (Ehrenberg) Pfitzer
   NM (Rio Brazos)

Neidium ampliatum (Ehrenberg) Krammer
   AZ (Southern Arizona Lakes)    NM (Charette Lake)

Neidium binode (Ehrenberg) Hustedt
   AZ (Grand Canyon, East Verde River)    NM (Conchas Lake, Santa Fe River, Rio Grande)

Neidium bisulcatum (Lagerstedt) Cleve
   AZ (Sheep's Crossing)

Neidium dubium (Ehrenberg) Cleve
   AZ (Lake Powell, Oak Creek, Chevelon Creek, Canyon Lake, San Pedro River, West Clear Creek)    NM (Conchas Lake, Rio Grande, Charette Lake)

Neidium dubium f. constrictum (Hustedt) Hustedt
   AZ (Lake Powell, Grand Canyon, Chevelon Creek, Canyon Lake)    NM (State record, Conchas Lake, Rio Grande, Rio Brazos)

Neidium hercynicum Mayer
   AZ (Sheep's Crossing)

Neidium iridis (Ehrenberg) P. T. Cleve
   AZ (91st Avenue WWTP)    NM (Pecos River, Rio Brazos, Santa Fe River)

Neidium productum (W. Smith) Cleve
   AZ (Southern Arizona Lakes)

Neidium vernale (Reichelt ex Hustedt) Metzeltin & Lange Bertalot
   SYN: Neidium iridis f. vernalis Reichelt ex Hustedt    AZ (Chevelon Creek)

Neidiomorpha binodeformis(Krammer) Cantonati et al.
   SYN: Neidium binodeforme Krammer in Krammer & Lange-Bertalot    AZ (West Clear Creek)

Nitzschia abridia Camburn in Camburn et al.
   AZ (San Pedro River)

Nitzschia accommodata Hustedt
   NM (Santa Fe River, Rio Salado)

Nitzschia acicularioides Hustedt
   AZ (San Pedro River, Rio Salado)

Nitzschia acicularis (Kützing) W. Smith
   AZ (Grand Canyon, Southern Arizona Lakes, Central Arizona Project, Oak Creek, Canyon Lake, Chevelon Creek, Big Lake Outlet, Cave Creek, Sunrise Lake, Rio Verde, San Pedro River, Gila River, Santa Cruz River, West Clear Creek)    NM (Railroad Canyon, Rio Grande, Rio Brazos, Charette Lake?, Ute Lake, Rito de Los Frijoles, Santa Fe River, Rio Grande)

Nitzschia acula (Kützing) Hantzsch in Rabenhorst
   AZ (Grand Canyon, East Verde River)    [Reported in error as N. acuta Hantzsch.]

Nitzschia agnita Hustedt
   AZ (San Pedro River, Rio Verde, West Clear Creek)

Nitzschia amphibia Grunow
   AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Chevelon Creek, Ayers Lake, Queen Creek, Rio Verde, , San Pedro River, Santa Cruz River, 91st Avenue WWTP, West Clear Creek)    NM (Elephant Butte Lake, Conchas Lake, Santa Rosa Lake, Rio Chama, Santa Fe River, Red River, Rio Grande, Rattlesnake Spring)    W TX (Ft. Davis CDRI)

Nitzschia amphibia f. frauenfeldii (Grunow) Lange-Bertalot
   SYN: Nitzschia amphibia var. frauenfeldii Grunow    NM (Rio Grande)

Nitzschia amphibioides Hustedt
   NM (Rio Grande)

Nitzschia angustatula Lange-Bertalot in Lange-Bertalot & Krammer
   AZ (San Pedro River, Rio Salado, 91st Avenue WWTP, Rio Verde, West Clear Creek)    NM (Rio Grande)

Nitzschia archibaldii Lange-Bertalot
   AZ (San Pedro River, West Clear Creek)

Nitzschia aurariae Cholnoky
   AZ (San Pedro River)

Nitzschia baccata Hustedt
   NM (Rio Grande)

Nitzschia biacrula Hohn & Hellerman
   AZ (San Pedro River)    NM (Rio Grande)

Nitzschia bicrena Hohn & Hellerman
   AZ (Grand Canyon)

Nitzschia bita Hohn & Hellerman
   AZ (Grand Canyon)

Nitzschia bremensis Hustedt
   NM (Elephant Butte Lake, Conchas Lake, Ute Lake)

Nitzschia brevissima Grunow in Van Heurck
   SYN: Nitzschia parvula Lewis    AZ (Oak Creek)

Nitzschia bulnheimiana (Rabenhorst) H.L. Smith
   SYN: Nitzschia frustulum var. bulnheimiana (Rabenhorst) Grunow    AZ (West Clear Creek)   NM (McAllister Lake)

Nitzschia capitellata Hustedt in Schmidt
   AZ (Lake Powell, Grand Canyon, Chevelon Creek, San Pedro River, Gila River, Santa Cruz River, Rio Verde, West Clear Creek)    NM (Rio Grande)

Nitzschia clausii Hantzsch
   AZ (Queen Creek, San Pedro River, 91st Avenue WWTP, Gila River, Rio Verde)    NM (Aguirre Springs, Rio Grande)

Nitzschia communis Rabenhorst
   AZ (Lake Powell, Grand Canyon, Chevelon Creek, Cave Creek, Queen Creek, East Verde River, Santa Cruz River, West Clear Creek)    NM (Aguirre Springs)    W TX (Ft. Davis CDRI)

Nitzschia commutata Grunow in Cleve & Grunow
   AZ (San Pedro River)

Nitzschia confinis Hustedt
   NM (Rio Grande)

Nitzschia dissipata (Kützing) Grunow
   AZ (Lake Powell, Grand Canyon, Central Arizona Project, Oak Creek, Canyon Lake, Chevelon Creek, Sycamore Creek, East Verde River, Tonto Creek, Cave Creek, Bartlett Lake, Rio Verde, Rio Salado, San Pedro River, 91st Avenue WWTP, Santa Cruz River, Gila River, West Clear Creek)    NM (Rio Chama, Conchas Lake, Elephant Butte Lake, McAllister Lake, Rio Grande, Rio Brazos, Charette Lake, Embudo Creek, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos)

Nitzschia dissipata var. media (Hantzsch) Grunow
   NM (Rio Chama, Conchas Lake, Rio Grande, Rio Brazos, Ute Lake, Embudo Creek, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River)

Nitzschia dubia W. Smith
   AZ (San Pedro River, West Clear Creek)

Nitzschia filiformis (W. Smith) Van Heurck
   AZ (Central Arizona Project, Canyon Lake, Chevelon Creek, San Pedro River, Rio Salado, Rio Verde, West Clear Creek)    NM (Rio Chama, Elephant Butte Lake, Conchas Lake, Ute Lake, Rio Grande)

Nitzschia filiformis var. conferta (Richter) Lange Bertalot
   SYN: Nitzschia accedens Hustedt    AZ (Lake Powell, San Pedro River)

Nitzschia flexoides Geitler
   AZ (West Clear Creek)    NM (Rio Chama, Ute Lake?)

Nitzschia fonticola Grunow in Cleve & Möller
   SYN: Nitzschia romana (Grunow) Grunow in Van Heurck    AZ (Oak Creek, Lake Powell, Grand Canyon, Central Arizona Project, Oak Creek, Canyon Lake, San Pedro River, Rio Salado, Gila River, Rio Verde, West Clear Creek)    NM (Cochiti Lake, Elephant Butte Lake, Rio Grande, Jemez River)

Nitzschia fonticola var. pelagica Hustedt
   AZ (Canyon Lake, Cave Creek, East Verde River)    [Lange-Bertalot has suggested that this taxon is probably synonymous with Nitzschia supralitorea Lange-Bertalot. It does not seem to be one of the taxa in the N. fonticola species group.]

Nitzschia frequens Hustedt
   NM (Rio Chama)

Nitzschia frustulum (Kützing) Grunow in Cleve & Grunow
   AZ (Lake Powell, Grand Canyon, Chevelon Creek, San Pedro River, Rio Salado, 91st Avenue WWTP, Gila River, Santa Cruz River, Rio Verde, West Clear Creek)    NM (McAllister Lake, Rio Chama, Rito de Los Frijoles, Santa Fe River, Red River, Rio Grande, Rio Pueblo de Taos, Embudo Creek, Jemez River)

Nitzschia frustulum var. perpusilla (Rabenhorst) Grunow in Van Heurck
   NM (Elephant Butte Lake)

Nitzschia frustulum var. subsalina Hustedt
   NM (McAllister Lake)

Nitzschia gandersheimiensis Krasske
   AZ (San Pedro River, Gila River, Santa Cruz River, Rio Verde)

Nitzschia gessneri Hustedt
   AZ (West Clear Creek)

Nitzschia gracilis Hantzsch
   AZ (Grand Canyon, Southern Arizona Lakes, San Pedro River, Rio Verde, West Clear Creek)    NM (Elephant Butte Lake, McAllister Lake, Rio Grande, Rio Brazos, Santa Fe River)

Nitzschia hantzschiana Rabenhorst
   AZ (Gila River)

Nitzschia heufleriana Grunow
   AZ (San Pedro River, West Clear Creek)    NM (Elephant Butte Lake)

Nitzschia homburgiensis Lange-Bertalot
   SYN: Nitzschia thermalis (Ehrenberg) Auerswald    NM (Elephant Butte Lake)

Nitzschia hybrida Grunow in Cleve & Grunow
   AZ (Grand Canyon)

Nitzschia incognita Legler & Krasske
   AZ (Rio Verde)

Nitzschia inconspicua Grunow
   AZ (San Pedro River, Rio Salado, 91st Avenue WWTP, Gila River, Santa Cruz River, Rio Verde, West Clear Creek)    NM (McAllister Lake, Rio Grande, Rio Brazos, San Juan River, Santa Rosa Lake)

Nitzschia cf. intermedia Hantzsch
   NM (Conchas Lake, Rio Brazos)

Nitzschia lacunarum Hustedt in Schmidt
   AZ (Grand Canyon, Chevelon Creek, San Pedro River)

Nitzschia lanceolata W. Smith
   NM (Charette Lake)

Nitzschia liebethruthii Rabenhorst
   AZ (San Pedro River, Rio Salado, 91st Avenue WWTP, West Clear Creek)

Nitzschia liebethruthii var. major Grunow in Cleve & Möller
   AZ (Rio Verde)

Nitzschia linearis (Agardh) W. Smith
   AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Central Arizona Project, East Turkey Creek, Sycamore Creek, East Verde River, Cave Creek, Oak Creek, Queen Creek, San Pedro River, Gila River, Santa Cruz River, Rio Verde, West Clear Creek)    NM (Elephant Butte Lake, Conchas Lake?, Rio Grande, Rio Brazos, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River)    W TX (Ft. Davis CDRI)

Nitzschia linearis var. tenuis (W. Smith) Grunow
   NM (McAllister Lake, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Grande)

Nitzschia lorenziana Grunow in Cleve & Grunow
   SYN: Nitzschia lorenziana var. subtilis Grunow in Cleve & Grunow    AZ (San Pedro River, Rio Salado)    NM (Rio Grande)

Nitzschia microcephala Grunow in Cleve & Möller
   AZ (Lake Powell, Grand Canyon, Chevelon Creek, Ayers Lake, Rio Verde, Canyon Lake, San Pedro River, Rio Salado, West Clear Creek, Bartlett Lake)    NM (Elephant Butte Lake, McAllister Lake)

Nitzschia nana Grunow in Van Heurck
   AZ (San Pedro River, Rio Salado, 91st Avenue WWTP, West Clear Creek)    NM (McAllister Lake)

Nitzschia obtusa W. Smith
   AZ (Chevelon Creek)

Nitzschia palea (Kützing) W. Smith
   AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Central Arizona Project, Oak Creek, Canyon Lake, Chevelon Creek, Cave Creek, East Verde River, San Pedro River, Rio Salado, 91st Avenue WWTP, Santa Cruz River, Gila River, Rio Verde, West Clear Creek)    NM (Conchas Lake, Elephant Butte Lake, McAllister Lake, Rio Grande, Rio Brazos, Santa Rosa Lake, Aguirre Springs, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River)    W TX (Laguna Prieta)

Nitzschia palea var. debilis (Kützing) Grunow in Cleve & Grunow
   AZ (San Pedro River, Rio Salado, 91st Avenue WWTP, Santa Cruz River, Rio Verde, West Clear Creek)

Nitzschia palea var. tenuirostris Grunow in Van Heurck
   AZ (San Pedro River, Rio Verde)

Nitzschia cf. palea (Kützing) W. Smith
   AZ (Rio Verde)

Nitzschia paleacea (Grunow) Grunow in Van Heurck
   SYN: Nitzschia holsatica Hustedt in Schmidt    AZ (Southern Arizona Lakes, Central Arizona Project, , San Pedro River, Gila River, West Clear Creek)    NM (Elephant Butte Lake, McAllister Lake)

Nitzschia parvula W. Smith
   AZ (San Pedro River)

Nitzschia pellucida Grunow in Cleve & Grunow
   AZ (Chevelon Creek)

Nitzschia perminuta (Grunow) M. Peragallo
   SYN: Nitzschia frustulum var. perminuta Grunow in Van Heurck    AZ (Lake Powell, San Pedro River, Rio Salado, 91st Avenue WWTP, Santa Cruz River, Gila River, Rio Verde, West Clear Creek)

Nitzschia perspicua Cholnoky
   AZ (San Pedro River)

Nitzschia pumila Hustedt
   AZ (San Pedro River)

Nitzschia pura Hustedt
   AZ (San Pedro River, Rio Verde)

Nitzschia pusilla Grunow emend. Lange Bertalot
   SYN: Nitzschia kuetzingiana Hilse    AZ (Lake Powell, Grand Canyon, Chevelon Creek)    NM (Elephant Butte Lake, Canyon, Chevelon Creek, San Pedro River, Rio Salado) NM (Elephant Butte Lake, Embudo Creek, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Grande, Rio Pueblo de Taos)

Nitzschia recta Hantzsch in Rabenhorst
   AZ (Grand Canyon, Southern Arizona Lakes, East Turkey Creek, Cave Creek, East Verde River, San Pedro River, Rio Verde, West Clear Creek)    NM (Rio Brazos, Ute Lake?, Rio Pueblo de Taos, Rio Grande)

Nitzschia scalaris (Ehrenberg) W. Smith
   W TX (East Sandia Spring)

Nitzschia sigma (Kützing) W. Smith
   AZ (Grand Canyon, Chevelon Creek, San Pedro River, Santa Cruz River, Rio Verde)    NM (Conchas Lake, Rio Grande, Jemez River)

Nitzschia sigmoidea (Nitzsch) W. Smith
   AZ (Central Arizona Project, Upper Lake Mary, Cave Creek, East Verde River, San Pedro River, Rio Verde, West Clear Creek)    NM (Bitter Lake, Elephant Butte Lake, Conchas Lake, Rio Grande, Rio Brazos, San Juan River, Santa Rosa Lake, Rito de Los Frijoles)

Nitzschia silicula Hustedt
   AZ (Chevelon Creek, San Pedro River)

Nitzschia siliqua Archibald
   AZ (San Pedro River)    NM (Rio Grande, Rito de Los Frijoles)

Nitzschia sinuata (Thwaites ex W. Smith) Grunow in Cleve & Grunow
   NM (Conchas Lake)

Nitzschia sinuata var. delognei (Grunow) Lange-Bertalot
   AZ (Queen Creek)

Nitzschia sinuata var. tabellaria (Grunow) Grunow in Van Heurck
   AZ (Lake Powell, Grand Canyon, Central Arizona Project, Oak Creek, Chevelon Creek, East Verde River, West Clear Creek)    NM (Conchas Lake, San Juan River, Santa Rosa Lake)

Nitzschia sociabilis Hustedt
   AZ (San Pedro River, Santa Cruz River, Rio Verde, West Clear Creek)    NM (Embudo Creek, Rio Chama, Rio Grande, Rio Pueblo de Taos)

Nitzschia solita Hustedt
   AZ (San Pedro River, Santa Cruz River, Gila River, Rio Verde, West Clear Creek)

Nitzschia spiculum Hustedt
   SYN: Nitzschia acicularioides Hustedt    NM (Rio Brazos)

Nitzschia subacicularis Hustedt in Schmidt
   AZ (San Pedro River, Rio Salado, West Clear Creek)

Nitzschia sublinearis Hustedt
   AZ (Southern Arizona Lakes, Chevelon Creek, San Pedro River)    NM (Conchas Lake)

Nitzschia subtilis Grunow in Cleve & Grunow
   SYN: Nitzschia linearis var. subtilis (Grunow) Hustedt    AZ (Canyon Lake, San Pedro River, Rio Verde, West Clear Creek)    NM (Ute Lake, Rio Grande, Rio Pueblo de Taos)

Nitzschia suchlandtii Hustedt
   AZ (San Pedro River)

Nitzschia supralitorea Lange-Bertalot
   AZ (San Pedro River, Rio Salado, Gila River, Rio Verde, West Clear Creek)

Nitzschia thermaloides Hustedt
   NM (Ute Lake)

Nitzschia tropica Hustedt
   AZ (San Pedro River, West Clear Creek)   NM (Rio Chama, Rio Grande, Red River

Nitzschia tubicola Grunow in Cleve & Grunow
   NM (Rio Grande)

Nitzschia umbonata (Ehrenberg) Lange-Bertalot
   AZ (Cave Creek, San Pedro River, Rio Salado, 91st Avenue WWTP)    NM (Santa Fe River, Rio Grande)

Nitzschia valdestriata Aleem & Hustedt
   NM (Conchas Lake)

Nitzschia cf. valdestriata Aleem & Hustedt
   AZ (Cave Creek)

Nitzschia vermicularis (Kützing) Hantzsch in Rabenhorst
   AZ (Lake Powell, Grand Canyon, Canyon Lake, San Pedro River)    NM (Elephant Butte Lake, Charette Lake, Santa Rosa Lake)

Nitzschia vermicularis f. angustior Grunow in Van Heurck
   NM (Ute Lake)

Nitzschia vitrea Norman
   AZ (San Pedro River)

Nitzschia vitrea var. salinarum Grunow
   NM (McAllister Lake)

Nitzschia sp. OU UL NAWQA KM
   AZ (San Pedro River)

Nitzschia sp. 1 NAWQA UMICH CZAB
   AZ (Rio Verde)

Nitzschia sp. 2 NAWQA UMICH CZAB
   AZ (91st Avenue WWTP)

Nitzschia sp. 3 NAWQA UMICH CZAB
   AZ (Rio Salado)

Nitzschia sp. 4 NAWQA UMICH CZAB
   AZ (San Pedro River)

Nitzschia sp. 5 NAWQA UMICH CZAB
   AZ (San Pedro River)

O-P

Opephora ansata Hohn & Hellerman
   AZ (Chevelon Creek)

Opephora olsenii M. Møller
   NM (Conchas Lake, McAllister Lake, San Juan River)

Parlibellus crucicula (W. Smith) Witkowski, Lange-Bertalot & Metzeltin
   SYN: Navicula crucicula (W. Smith) Donkin    NM (Elephant Butte Lake, Conchas Lake)

Parlibellus protracta (Grunow) Witkowski, Lange-Bertalot & Metzeltin
   SYN: Navicula protracta (Grunow in Cleve & Grunow) Cleve.    AZ (Gila River)   NM (Rio Grande)

Pinnularia abaujensis var. subundulata (Mayer ex Hustedt) Patrick
   AZ (Upper Lake Mary)    NM (Rio Brazos) [Krammer claims that Patrick has followed R. Ross in mixing forms of Pinnularia gibba Ehrenberg and Pinnularia gibbiformis Krammer under the name Pinnularia abaujensis (Pantocsek) Ross. He also claims that Mayer's f. subundulata does not belong in the gibba-group. It appears that reexamination of specimens in the light of Krammer's recent revision will be required to correctly identify this taxon. It may prove to be Pinnularia subgibba var. undulata Krammer.]

Pinnularia angusta (Cleve) Krammer
   SYN: Pinnularia mesolepta var. angusta Cleve    AZ (Sheep's Crossing)

Pinnularia appendiculata (Agardh) Cleve
   AZ (Grand Canyon, Ayers Lake, 91st Avenue WWTP)    NM (Rattlesnake Spring)    W TX (Rio Bosque)

Pinnularia biceps Gregory
   SYN: Pinnularia interrupta W. Smith    AZ (San Pedro River)   NM (Santa Fe River)

Pinnularia borealis Ehrenberg
   AZ (Southern Arizona Lakes, Big Lake Outlet, Queen Creek)    NM (Brazos River, McAllister Lake, Aguirre Spring, , Rito de Los Frijoles, Rio Grande)

Pinnularia borealis var. rectangularis Carlson
   AZ (Grand Canyon, Chevelon Creek, San Pedro River, West Clear Creekl)

Pinnularia brandelii Cleve
   NM (Rio Brazos)

Pinnularia brebissonii (Kützing) Rabenhorst
   AZ (Grand Canyon, Chevelon Creek)    NM (State record, Rio Grande)

Pinnularia brevicostata Cleve
   NM (Rio Brazos)

Pinnularia divergens W. Smith
   AZ (Big Lake Outlet)

Pinnularia divergens var. bacillaris (M. Peragallo) Mills
   AZ (Sheep's Crossing)

Pinnularia divergentissima (Grunow in Van Heurck) Cleve
   AZ (Grand Canyon)

Pinnularia divergentissima var. subrostrata Cleve-Euler
  SYN: Pinnularia subrostrata (A. Cleve) Cleve-Euler   AZ (San Pedro River)

Pinnularia dubitabilis Hustedt
   AZ (Souhern Arizona Lakes)

Pinnularia gibba Ehrenberg
   AZ (91st Avanue WWTP)

Pinnularia gibba var. linearis Hustedt
   NM (Rio Brazos)

Pinnularia cf. gibba Ehrenberg
   NM (Rio Brazos)

Pinnularia grunowii Krammer
   AZ (Sunrise Lake)

Pinnularia intermedia (Lagerstedt) Cleve
   AZ (Chevelon Creek)

Pinnularia joculata (Manguin) Krammer
   SYN: Pinnularia interrupta var. joculata Manguin in Bourelly & Manguin    AZ (91st Avenue WWTP)

Pinnularia latevittata Cleve
   AZ (Sheep's Crossing)

Pinnularia lundii Hustedt
   AZ (Sheep's Crossing)

Pinnularia mayeri Krammer
   SYN: Pinnularia braunii var. amphicephala (Mayer) Hustedt    AZ (Southern Arizona Lakes)

Pinnularia mesogongyla Ehrenberg
   AZ (Southern Arizona Lakes)

Pinnularia mesolepta (Ehrenberg) W. Smith
   NM (Sata Fe River)

Pinnularia microstauron (Ehrenberg) Cleve
   AZ (Lake Powell, 91st Avenue WWTP, Santa Cruz River, Rio Verde)    NM (State record, Rio Brazos, Santa Fe River)

Pinnularia mormonorum (Grunow) Boyer
   AZ (Chevelon Creek)

Pinnularia neomajor Krammer
   SYN: Pinnularia major (Kutzing) Rabenhorst    AZ (Sheep's Crossing)    NM (Santa Rosa Lake, Rito de Los Frijoles, Santa Fe River)

Pinnularia nodosa (Ehrenberg) W. Smith
   AZ (Big Lake Outlet)

Pinnularia notabilis Krammer in Krammer & Lange-Bertalot
   NM (Rio Brazos)

Pinnularia ovata Krammer
   SYN: Pinnularia divergens var. elliptica (Grunow) Cleve    NM (Elephant Butte Lake)

Pinnularia parvulissima Krammer
   W TX (Laguna Prieta) Note: This species may not be previously known from the United States (type locality: Dresden). It was very abundant in the Laguna Prieta samples and matches this species closely.

Pinnularia stomatophora (Grunow) Cleve
   NM (Santa Rosa Lake)

Pinnularia subcapitata Gregory
   AZ (Central Arizona Project, Sunrise Lake, Sheep's Crossing, San Pedro River, Rio Salado, Rio Verde)

Pinnularia subcapitata var. paucistriata (Grunow in Van Heurck) Cleve
   AZ (Lake Powell)

Pinnularia subcommutata Krammer
   NM (Rio Brazos)

Pinnularia subgibba Krammer
   NM (Rio Brazos)

Pinnularia subgibba var. undulata Krammer
   AZ (Big Lake Outlet)    NM (Rio Brazos)

Pinnularia substreptoraphe K.Krammer
   SYN: Pinnularia streptoraphe var. parva Krammer    NM (Santa Rosa Lake)

Pinnularia sudetica (Hilse) Hilse in Rabenhorst
   NM (Rio Brazos)

Pinnularia termitina (Ehrenberg) Patrick
   NM (Pecos River)

Pinnularia viridiformis Krammer
   SYN: Pinnularia viridis var. minor Cleve    AZ (Central Arizona Project)

Pinnularia viridis (Nitzsch) Ehrenberg
   AZ (Southern Arizona Lakes, Chevelon Creek, Big Lake Outlet, Sheep's Crossing)    NM (State record)

Placoneis cf. abiskoensis (Hustedt) Lange-Bertalot & Metzeltin
   AZ (Big Lake Outlet)

Placoneis anglica (Ralfs in Pritchard) Cox
   SYN: Navicula anglica Ralfs in Pritchard    AZ (Lake Powell, Central Arizona Project)    NM (Conchas Lake, Elephant Butte Lake, Rio Grande)

Placoneis clementis (Grunow) Cox
   SYN: Navicula clementis Grunow    NM (Rio Brazos, Santa Fe River)

Placoneis constans (Hustedt) Cox
   SYN: Navicula constans Hustedt    NM (Rio Grande)

Placoneis elginensis (Gregory) Cox
   SYN: Navicula elginensis (Gregory) Ralfs    AZ (Chevelon Creek, Tonto Creek, Rio Salado, 91st Avenue WWTP. West Clear Creek)    NM (Elephant Butte Lake, Pecos River, Rio Grande, Rio Brazos, Cochiti Lake, San Juan River, Ute Lake)

Placoneis elginensis f. exigua (Gregory) Bukhtiyarova
   SYN: Navicula gastrum var. exigua (Gregory) Grunow in Van Heurck, Navicula exigua (Gregory) Grunow in Van Heurck    AZ (Canyon Lake, Chevelon Creek, San Pedro River)    NM (Rio Brazos)

Placoneis gastrum (Ehrenberg) Mereschkowsky
   SYN: Navicula gastrum (Ehrenberg) Kützing.    NM (Conchas Lake)

Placoneis hambergii (Hustedt) Broder
   v SYN: Navicula hambergii Hustedt    AZ (San Pedro River)    NM (Rio Brazos)

Placoneis lata (M. Peragallo) Lowe in Johansen et al.
   SYN: Navicula elginensis var. lata (M. Peragallo) Patrick    NM (Rio Brazos)

Placoneis placentula (Ehrenberg) Mereschkowsky
   SYN: Navicula placentula (Ehrenberg) Kützing    NM (Elephant Butte Lake, Conchas Lake)

Placoneis pseudanglica Cox
   SYN: Navicula pseudanglica Lange-Bertalot in Krammer & Lange-Bertalot, Placoneis anglophila (Lange-Bertalot) Lange-Bertalot in Metzeltin et al.    AZ (San Pedro River, Rio Salado, Rio Verde, West Clear Creek)  NM (Charette Lake, Santa Rosa Lake)

Placoneis signata (Hustedt) A. Mayama in S. Mayama & A. Kawashima
   SYN: Navicula gastrum var. signata Hustedt in Schmidt et al.    NM (Elephant Butte Lake, Conchas Lake)

Placoneis significans Lange-Bertalot in Metzeltin et al.
   SYN: Navicula exigua var. signata Hustedt    AZ (West Clear Creek)

Placoneis symmetrica (Hustedt) Lange-Bertalot in Metzeltin et al.
   SYN: Navicula constans var. symmetrica Hustedt    NM (Rio Grande)

Plagiotropis arizonica Czarnecki & Blinn
   AZ (Chevelon Creek)

Plagiotropis lepidopteravar. proboscidea (Cleve) Reimer in Patrick and Reimer
   AZ (Chevelon Creek, Canyon Lake, Rio Salado)    NM (Elephant Butte Lake, Conchas Lake, Ute Lake)

Planothidium biporomum (Hohn & Hellerman) Lange-Bertalot
   SYN: Achnanthes biporoma Hohn & Hellerman    NM (Rito de Los Frijoles)

Planothidium conspicuum (Mayer) Aboal in Aboal et al.
   SYN: Achnanthes conspicua Mayer    NM (McAllister Lake)

Planothidium delicatulum (Kützing) Round & Bukhtiyarova
   SYN: Achnanthes delicatula Kützing    AZ (Rio Salado, Gila River)    NM (Elephant Butte Lake, McAllister Lake, Rio Grande, Charette Lake)

Planothidium dubium (Grunow) Round & Bukhtiyarova
   SYN: Achnanthes lanceolata var. dubia Grunow    AZ (Lake Powell, Grand Canyon, Oak Creek, East Verde River, Tonto Creek, West Clear Creek)  Embudo Creek, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Grande, Rio Pueblo de Taos)

Planothidium ellipticum (Cleve) Round & Bukhtiyarova
   SYN: Achnanthes lanceolata var. elliptica Cleve    AZ (Southern Arizona Lakes)    NM (Rio Brazos)

Planothidium frequentissimum (Lange-Bertalot) Lange-Bertalot
   AZ (San Pedro River, West Clear Creek)

Planothidium granum (Hohn & Hellerman) Lange-Bertalot
   SYN: Achnanthes grana Hohn & Hellerman    AZ (San Pedro River, West Clear Creek)

Planothidium hauckianum (Grunow) Round & Bukhtiyarova
   SYN: Achnanthes hauckiana Grunow    AZ (Chevelon Creek)    NM (Conchas Lake, McAllister Lake, Rio Grande)

Planothidium hauckianum var. rostratum (Schulz) Bukhtiyarova
   SYN: Achnanthes hauckiana var. rostrata Schulz ex Hustedt    AZ (Chevelon Creek)    NM (Jemez River, Rio Grande)

Planothidium lanceolatum (Brébisson) Round & Bukhtiyarova
   SYN: Achnanthes lanceolata Brébisson; Achnanthes lanceolata var. capitata O. Müller    AZ (Grand Canyon, Central Arizona Project, Oak Creek, Southern Arizona Lakes, Canyon Lake, Chevelon Creek, East Turkey Creek, East Verde River, Tonto Creek, Cave Creek, Sunrise Lake, Rio Verde, Rio Salado, 91st Avenue WWTP, Santa Cruz River, San Pedro River, Gila River, West Clear Creek)    NM (State Record, Conchas Lake, Rio Chama, Elephant Butte Lake, McAllister Lake, Rio Grande, Rio Brazos, San Juan River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos, Rattlesnake Spring)

Planothidium lanceolatum var. omissum (Reimer) Andresen, Stoermer, & Kreis
   SYN: Achnanthes lanceolata var. omissa Reimer in Patrick & Reimer    AZ (Grand Canyon)

Planothidium lanceolatum f. ventricosa (Hustedt) Bukhtiyarova
   SYN: Achnanthes lanceolata var. ventricosa Hustedt    NM (San Juan River)

Planothidium rostratum (Østrup) Round & Bukhtiyarova
   SYN: Achnanthes lanceolata var. rostrata (Østrup) Lange-Bertalot    AZ (Tonto Creek, Oak Creek, Cave Creek, Rio Verde, San Pedro River, West Clear Creek)    NM (Rio Grande, San Juan River)

Platessa conspicua (Mayer) Lange-Bertalot in Krammer & Lange-Bertalot
   SYN: Achnanthes conspicua Mayer    AZ (Rio Salado, 91st Avenue WWTP, Santa Cruz River, West Clear Creek)    NM (McAllister Lake)

Platessa montana (Krasske) Lange-Bertalot in Krammer & Lange-Bertalot
   SYN: Achnanthes montana Krasske    AZ (Santa Cruz River, San Pedro River)

Platessa rupestris (Krasske) Lange-Bertalot in Krammer & Lange-Bertalot
   SYN: Achnanthes rupestris Krasske    AZ (San Pedro River)

Platessa ziegleri (Lange-Bertalot) Lange-Bertalot in Krammer & Lange-Bertalot
   SYN: Achnanthes ziegleri Lange-Bertalot    AZ (Santa Cruz River)

Playaensis circumfimbria Spaulding & Kociolek
   NM (Payton Lake)

Playaensis furtiva Spaulding & Kociolek
   NM (Payton Lake)

Pleurosigma angulatum (Quekett) W. Smith
   AZ (San Pedro River, Gila River, Santa Cruz River, Rio Verde)

Pleurosigma delicatulum W. Smith
   AZ (Lake Powell, Grand Canyon, Central Arizona Project, Chevelon Creek, Saguaro Lake, Rio Salado)    NM (Charette Lake)

Pleurosigma elongatum W. Smith
   NM (McAllister Lake)    W TX (Diamond Y Spring)

Pleurosigma salinarum (Grunow) Grunow in Cleve & Grunow
   AZ (San Pedro River, Gila River)    W TX (Diamond Y Spring)

Pleurosira laevis (Ehrenberg) Compère
   SYN: Biddulphia laevis Ehrenberg    AZ (Grand Canyon, Rio Salado, Gila River, West Clear Creek)    NM (Rio Chama, Rio Grande)    W TX (Ft. Davis CDRI, East Sandia Spring)

Proschkinia longirostris (Hustedt) D. Mann in Round et al.
   SYN: Navicula longirostris Hustedt    AZ (Lake Powell, Grand Canyon)

Psammodictyon constrictum (Gregory) D. Mann in Round et al.
   SYN: Nitzschia constricta (Gregory) Grunow in Cleve & Grunow    AZ (Rio Verde, Gila River)

Psammothidium grischunum (Wuthrich) Bukhtiyarova & Round
   SYN: SYN: Achnanthes grischuna Wuthrich    AZ (San Pedro River, Santa Cruz River, 91st Avenue WWTP)

Psammothidium levanderi (Hustedt) Bukhtiyarova & Round
   SYN: Achnanthes levanderi Hustedt    AZ (Sheep's Crossing)

Psammothidium marginulatum (Grunow) Bukhtiyarova & Round
   SYN: Achnanthes marginulata Grunow in Cleve & Grunow    NM (Rito de Los Frijoles)

Psammothidium sacculum (Carter) Bukhtiyarova in Bukhtiyarova & Round
   SYN: Achnanthes sacculus Carter in Carter & Bailey-Watts    AZ (San Pedro River, Gila River)

Psammothidium ventralis (Krasske) Bukhtiyarova & Round
   AZ (West Clear Creek)

Pseudopodosira elliptica (Schumann) Edlund, Morales & Spaulding
   SYN: Fragilaria elliptica Schumann, Staurosira elliptica (Schumann) Williams & Round    AZ (West Clear Creek, San Pedro River)    NM (Conchas Lake)

Pseudostaurosira binodis (Ehrenberg) Edlund in Edlund et al.
   SYN: Fragilaria construens var. binodis (Ehrenberg) Grunow    AZ (Chevelon Creek, Rio Verde, West Clear Creek)    NM (Elephant Butte Lake, Rio Grande, San Juan River, Ute Lake)

Pseudostaurosira brevistriata (Grunow in Van Heurck) Williams & Round
   SYN: Fragilaria brevistriata Grunow in Van Heurck    AZ (Chevelon Creek, East Turkey Creek, Ayers Lake, Canyon Lake, West Clear Creek, San Pedro River, Rio Salado, Gila River, Rio Verde)    NM (Conchas Lake, McAllister Lake, Rio Grande, Ute Lake)

Pseudostaurosira brevistriata var. inflata (Pantocsek) Edlund
   SYN: Fragilaria brevistriata var. inflata (Pantocsek) Hustedt    AZ (Canyon Lake)  NM (Rio Grande)

Pseudostaurosira parasitica (W. Smith) Morales
   SYN: Fragilaria parasitica (W. Smith) Grunow    AZ (West Clear Creek)   NM (Rio Grande, Jemez River)

Pseudostaurosira parasitica var. subconstricta ((Grunow in Van Heurck) Morales
   SYN: Synedra parasitica var. subconstricta Grunow in Van Heurck    AZ (West Clear Creek)  NM (Rio Grande)

Pseudostaurosira subsalina (Hustedt) Morales
   SYN: Fragilaria construens var. subsalina Hustedt    NM (McAllister Lake)

Punctastriata lancettula (Schumann) Hamilton & Siver
   SYN: Fragilaria pinnata var. lancettula (Schumann) Hustedt in Schmidt    NM (Rio Grande)

Puncticulata bodanica (Grunow in Schneider) Håkansson
   SYN: Cyclotella bodanica Grunow in Schneider    NM (San Juan River)

Puncticulata comta (Ehrenberg) Håkansson
   SYN: Cyclotella comta (Ehrenberg) Kützing    NM (Rio Brazos)

Puncticulata radiosa (Lemmermann) Håkansson
   SYN: Cyclotella comta var. radiosa Grunow in Van Heurck    NM (Rio Brazos)

R-S-T-U

Reimeria sinuata (Gregory) Kociolek & Stoermer
   SYN: Cymbella sinuata Gregory    AZ (Grand Canyon, East Turkey Creek, East Verde River, Tonto Creek, Oak Creek, Cave Creek, Rio Salado, San Pedro River, Rio Verde, West Clear Creek)    NM (Elephant Butte Lake, Conchas Lake, Rio Grande, Rio Brazos, San Juan River, Rio Chama, Embudo Creek, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos)

Reimeria sinuata f. antiqua (Grunow) Kociolek & Stoermer
   NM (Rio Chama, Rio Grande, Jemez River)

Rhoicosphenia abbreviata (Agardh) Lange Bertalot
   SYN: Rhoicosphenia curvata (Kützing) Grunow    AZ (Grand Canyon, Peña Blanca Lake, Chevelon Creek, East Turkey Creek, Big Lake Outlet, Sycamore Creek, Tonto Creek, Cave Creek, Sunrise Lake, Oak Creek, Big Lake, Queen Creek, Bartlett Lake, Rio Verde, Rio Salado, West Clear Creek, San Pedro River, Gila River, Santa Cruz River, Canyon Lake)    NM (Carlito Spring, Railroad Canyon, Conchas Lake, McAllister Lake, Rio Grande, Rio Brazos, Santa Rosa Lake, San Juan River, Rio Chama, Jemez River, Rito de Los Frijoles, Santa Fe River)

Rhopalodia acuminata Krammer in Lange-Bertalot & Krammer
   AZ (San Pedro River)

Rhopalodia brebissonii Krammer in Lange-Bertalot & Krammer
   AZ (San Pedro River)

Rhopalodia constricta (W. Smith) Krammer in Lange-Bertalot & Krammer
   NM (McAllister Lake)

Rhopalodia gibba (Ehrenberg) O. Müller
   AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Central Arizona Project, Upper Lake Mary, Chevelon Creek, Sycamore Creek, Hawley Lake, Sunrise Lake, Ayers Lake, East Verde River, Bartlett Lake, San Pedro River, Rio Salado, Gila River, Rio Verde, West Clear Creek)    NM (State record, Elephant Butte Lake, Conchas Lake, Rio Grande, Santa Rosa Lake, San Juan River, Ute Lake, Rio Chama, Rito de Los Frijoles)    W TX (Palo Pinto Canyon)

Rhopalodia gibba var. minuta Krammer
   NM (McAllister Lake, Santa Rosa Lake)

Rhopalodia gibba var. ventricosa (Kützing) Peragallo & Peragallo
   AZ (Grand Canyon, Central Arizona Project, Chevelon Creek)    NM (Conchas Lake, McAllister Lake, Rio Brazos, San Juan River, Ute Lake, Santa Rosa Lake)    W TX (Shafter)

Rhopalodia gibberula (Ehrenberg) O. Müller
   AZ (Chevelon Creek, , San Pedro River, Rio Salado, Santa Cruz River, Rio Verde, West Clear Creek)    NM (State Record, McAllister Lake, Charette Lake, San Juan River, Rio Chama, Santa Fe River, Rio Grande, Rio Pueblo de Taos)

Rhopalodia gibberula var. vanheurckii O. Müller
   AZ (Lake Powell, Grand Cayon, Chevelon Creek, East Verde River, Ayers Lake, Queen Creek, Rio Verde)    NM (Elephant Butte Lake, Rio Grande, San Juan River)    W TX (Diamond Y Spring)

Rhopalodia musculus (Kützing) O.F. Müller
   NM (McAllister Lake, San Juan River)

Rhopalodia operculata (Agardh) Håkansson
   AZ (Gila River)

Rossithidium linearis (W. Smith) Round & Bukhtiyarova
   SYN: Achnanthes linearis (W. Sm.) Grunow    AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Chevelon Creek, San Pedro River)

Rossithidium pusillum (Grunow) Round & Bukhtiyarova
   SYN: Achnanthes linearis var. pusilla Grunow in Cleve & Grunow    AZ (Grand Canyon)

Scoliopleura peisonis Grunow
   AZ (Chevelon Creek)

Sellaphora bacillum (Ehrenberg) D. Mann
   SYN: Navicula bacillum Ehrenberg    AZ (Grand Canyon, Central Arizona Project, East Verde River, San Pedro River, Rio Salado, West Clear Creek)    NM (Elephant Butte Lake, Rio Brazos, Rio Grande)

Sellaphora cf. disjuncta (Hustedt) D. Mann
   SYN: Navicula disjuncta Hustedt    NM (Carlito Spring)

Sellaphora laevissima (Kützing) D. Mann
   SYN: Navicula laevissima Kützing    AZ (Southern Arizona Lakes)    NM (Rio Brazos, San Juan River, Rio Grande)

Sellaphora mutata (Krasske) Lange-Bertalot in Lange-Bertalot et al.
   SYN: Navicula pupula var. mutata (Krasske) Hustedt    AZ (San Pedro River)    NM (Rio Chama, Rito de Los Frijoles, Santa Fe River, Rio Grande)

Sellaphora pupula (Kützing) Mereschkowsky
   SYN: Navicula pupula Kützing, Navicula pupula var. capitata Skvortsow & Meyer    AZ (Lake Powell, Grand Canyon, Central Arizona Project, Canyon Lake, Chevelon Creek, Sycamore Creek, East Verde River, Tonto Creek, Cave Creek, Oak Creek, Ayers Lake, Bartlett Lake, 91st Avenue WWTP, Santa Cruz River, Rio Verde, Gila River, San Pedro River, Rio Salado, West Clear Creek)    NM (San Juan River, Charette Lake, Ute Lake, Conchas Lake, Elephant Butte Lake, McAllister Lake, Rio Grande, Rio Brazos, Santa Rosa Lake, Rio Chama, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos)

Sellaphora pupula var. capitata Skvortzow & Meyer
   W TX (Palo Pinto Canyon)

Sellaphora cf. radiosa (Hustedt) Kobayasi in Mayama et al.
   SYN: Navicula seminulum var. radiosa Hustedt    AZ (Rio Verde)

Sellaphora rectangularis (Gregory) Lange Bertalot & Metzeltin
   SYN: Navicula pupula var. rectangularis (Gregory) Grunow in Cleve & Grunow    AZ (Lake Powell, Grand Canyon, Southern Arizona Lakes, Chevelon Creek, Sunrise Lake, Canyon Lake)    NM (Conchas Lake, Elephant Butte Lake, Rio Brazos, Rio Chama, Rito de Los Frijoles, Rio Grande)    W TX (Laguna Prieta)

Sellaphora rostrata (Hustedt) Johansen in Johansen et al.
   SYN: Navicula pupula var. rostrata (Hustedt) Hustedt    NM (Conchas Lake)

Sellaphora seminulum (Grunow) D. Mann
   SYN: Navicula seminulum Grunow    AZ (Lake Powell, Southern Arizona Lakes, Cave Creek, San Pedro River, Rio Salado, 91st Avenue WWTP, Santa Cruz River, Rio Verde)    NM (Aguirre Springs, Conchas Lake, Rio Chama, Rito de Los Frijoles, Santa Fe River, Red River, Rio Grande)

Sellaphora stroemii (Hustedt) Kobayasi in Mayama et al.
   SYN: Navicula stroemii Hustedt    AZ (West Clear Creek)

Seminavis pusilla (Grunow in Schmidt) Cox & Reid
   SYN: Cymbella pusilla Grunow in Schmidt, Navicymbula pusilla (Grunow in Schmidt) Krammer    AZ (Lake Powell, Grand Canyon, Chevelon Creek)    NM (McAllister Lake)

Simonsenia delognei (Grunow) Lange-Bertalot
   AZ (San Pedro River, West Clear Creek)

Skeletonema subsalsum (Cleve-Euler) Bethge
   NM (McAllister Lake)

Stauroneis anceps Ehrenberg
   AZ (Lake Powell, Grand Canyon, Upper Lake Mary, San Pedro River, Gila River)    NM (State record, Conchas Lake, Rio Grande)

Stauroneis borrichii (Petersen) Lund
   AZ (91st Avenue WWTP, Big Lake Outlet, Tonto Creek)

Stauroneis cf. conspicua Metzeltin & Lange-Bertalot
   W TX (Laguna Prieta)

Stauroneis desiderata P.T. Cleve
   NM (Elephant Butte Lake)

Stauroneis gracilior Reichardt in Lange-Bertalot
   SYN: Stauroneis anceps f. gracilis Rabenhorst    AZ (Sunrise Lake)

Stauroneis gracilis Ehrenberg
   SYN: Stauroneis phoenicenteron f. gracilis (Ehrenberg) Hustedt    AZ (Sheep's Crossing)    NM (Rio Brazos)

Stauroneis italica Lange-Bertalot et al.
   AZ (East Verde River)

Stauroneis kriegeri Patrick
   AZ (Tonto Creek, Sheep's Crossing)    NM (Santa Fe River)

Stauroneis lapponica A.Cleve
   NM (Ute Lake)

Stauroneis leguminopsis Lange-Bertalot & Krammer
   AZ (Big Lake Outlet)

Stauroneis phoenicenteron (Nitzsch) Ehrenberg
   AZ (Upper Lake Mary, Rio Salado, Rio Verde)    NM (State record, Rio Brazos)

Stauroneis reichardtii Lange-Bertalot et al.
   AZ (A-1 Lake)

Stauroneis smithii Grunow
   AZ (Grand Canyon, East Verde River, Tonto Creek, Cave Creek, San Pedro River)    NM (Carlito Spring, Conchas Lake, Pecos River, Rio Grande)

Stauroneis subgracilis Lange-Bertalot & Krammer
   AZ (Big Lake Outlet, Sunrise Lake)

Stauroneis tackei (Hustedt) Krammer & Lange-Bertalot
   NM (Charette Lake, Ute Lake)

Stauroneis sp. 7 Carter
   AZ (Sunrise Lake, Cave Creek, Seven Springs Wash)   NM (Aguirre Springs)    W TX (Laguna Prieta)

Stauroneis sp. 8 Carter
   AZ (Big Lake Outlet)

Stauroneis sp. 9 Carter
   S TX (Laguna Prieta)

Staurophora wislouchii (Poretsky & Anissimova) D. Mann in Round et al.
   SYN: Stauroneis wislouchii Poretsky & Anissimova    NM (Elephant Butte Lake)

Staurosira construens Ehrenberg
   SYN: Fragilaria construens (Ehrenberg) Grunow    AZ (Southern Arizona Lakes, Canyon Lake, West Clear Creek)    NM (Rio Grande, Rio Brazos, San Juan River, Rito de Los Frijoles, Rattlesnake Spring)

Staurosira construens var. pumila (Grunow) Kingston
   SYN: Fragilaria construens var. pumila Grunow in Van Heurck    AZ (Sheep's Crossing, West Clear Creek)    NM (McAllister Lake, Rio Brazos, Rito de Los Frijoles, Rio Grande, Rio Pueblo de Taos)

Staurosira construens var. venter (Ehrenberg) Hamilton in Hamilton, Poulin, Charles and Angell
   SYN: Fragilaria construens var. venter (Ehrenberg) Grunow    AZ (Chevelon Creek, Ayers Lake, Rio Verde, West Clear Creek, San Pedro River)    NM (McAllister Lake, Rio Grande, Rio Brazos, Santa Rosa Lake, Rio Chama, Rito de Los Frijoles, Santa Fe River, Rio Pueblo de Taos)

Staurosirella leptostauron (Ehrenberg) Williams & Round
   SYN: Fragilaria leptostauron (Ehrenberg) Hustedt    AZ (Tonto Creek, Oak Creek, San Pedro River, Rio Verde, West Clear Creek)    NM (Cow Creek, Pecos River, Rio Grande, Rio Brazos, San Juan River, Rito de Los Frijoles, Red River, Rio Pueblo de Taos)

Staurosirella martyi (Heribaud) Morales & Manoylov
   SYN: Opephora martyi Heribaud    NM (Rito de Los Frijoles)

Staurosirella pinnata (Ehrenberg) Williams & Round
   SYN: Fragilaria pinnata Ehrenberg    AZ (San Pedro River, Rio Salado, 91st Avenue WWTP, Santa Cruz River, Rio Verde, West Clear Creek)    NM (McAllister Lake, Rio Grande, San Juan River, Embudo Creek, Rio Chama, Ritode Los Frijoles, Santa Fe River, Red River)

Staurosirella pinnata var. intercedens (Grunow) Hamilton
   SYN: Fragilaria pinnata var. intercedens Grunow in Van Heurck    NM (San Juan River)

Staurosirella pinnata var.lancettula (Schumann) Siver & Hamilton in Siver et al.
   SYN: Fragilaria pinnata var. lancettula (Schumann) Hustedt   AZ (Rio Salado, Rio Verde, West Clear Creek)    NM (Rio Grande)

Staurosirella pinnata var. subrotunda(Mayer) Flower
   SYN: Fragilaria pinnata var. subrotunda Mayer    NM (Rio Grande)

Stephanocyclus meneghiniana (Kützing) Skabitschevsky
   SYN: Cyclotella meneghiniana Kützing, Cyclotella kuetzingiana Thwaites    AZ (Lake Powell, Oak Creek, Beaver Creek, Canyon Lake, Chevelon Creek, Big Lake Outlet, Sycamore Creek, East Verde River, Cave Creek, Ayers Lake, Queen Creek, Rio Salado, San Pedro River, Santa Cruz River, Gila River, Rio Verde, West Clear Creek)    NM (Elephant Butte Lake, Conchas Lake, Rio Brazos, Santa Rosa Lake, San Juan River, Ute Lake, Jemez River, Santa Fe River, Rio Grande)    W TX (Diamond Y Spring)

Stephanodiscus alpinus Hustedt
   NM (Rio Chama, Cochiti Lake, Ute Lake)

Stephanodiscus carconensis f. minor Grunow
   NM (Elephant Butte Lake)

Stephanodiscus hantzschii Grunow in Cleve & Grunow
   AZ (Canyon Lake, Rio Verde, San Pedro River)    NM (Elephant Butte Lake, Rio Grande)

Stephanodiscus medius Håkansson
   NM (Santa Rosa Lake, Jemez River, Rio Grande)

Stephanodiscus niagarae Ehrenberg
   AZ (Sunrise Lake)    NM (Elephant Butte Lake, Cochiti Lake, Charette Lake, Ute Lake, Santa Rosa Lake, Rio Grande)

Stephanodiscus rotula (Kützing) Hendey
   SYN: Stephanodiscus astraea (Ehrenberg) Grunow    AZ (Canyon Lake)    NM (Charette Lake, Elephant Butte Lake, Conchas Lake)

Stephanodiscus rotula var. minutula (Kützing) Ross & Sims
   SYN: Stephanodiscus astraea var. minutula (Kützing) Grunow in Van Heurck   AZ (Canyon Lake)    NM (Rio Grande)

Stephanodiscus sp. 1 NAWQA UMICH CZAB
   NM (Rio Grande)

Surirella angusta Kützing
   AZ (Lake Powell, Grand Canyon, Central Arizona Project, Big Lake Outlet, Upper Lake Mary, Sycamore Creek, East Verde River, Tonto Creek, Cave Creek, Sunrise Lake, Oak Creek, Queen Creek, Bartlett Lake, Rio Verde, San Pedro River, West Clear Creek)    NM (Conchas Lake, Elephant Butte Lake, Storrie Lake, Rio Grande, Santa Rosa Lake, San Juan River, Embudo Creek, Rio Chama, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos)

Surirella brebissonii Krammer & Lange-Bertalot
   AZ (San Pedro River)    NM (Santa Rosa Lake, San Juan River, Ute Lake)

Surirella brebissonii var. kuetzingii Krammer & Lange-Bertalot
   AZ (Rio Verde, East Verde River, San Pedro River)    NM (Rio Chama, Elephant Butte Lake, Rio Grande, Rio Brazos, Santa Rosa Lake, San Juan River, Ute Lake)

Surirella brightwellii W. Smith
   AZ (Grand Canyon, Cholla Lake, Chevelon Creek, San Pedro River)    NM (Red River)

Surirella capronii Brébisson & Kitton
   AZ (East Verde River)

Surirella elegans Ehrenberg
   AZ (Southern Arizona Lakes)

Surirella excellens Hustedt
   AZ (Sheep's Crossing)

Surirella gracilis (W. Smith) Grunow
   AZ (San Pedro River)

Surirella hoefleri Hustedt
   AZ (San Pedro River)

Surirella linearis W. Smith
   AZ (Southern Arizona Lakes)    NM (Conchas Lake, Elephant Butte Lake))

Surirella minuta Brébisson in Kützing
   SYN: Surirella ovata var. pinnata (W. Smith) Brun    AZ (Grand Canyon, San Pedro River, West Clear Creek)    NM (Rio Chama, Conchas Lake, Elephant Butte Lake, Rio Grande, Jemez River, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos)

Surirella ovalis Brébisson
   AZ (Lake Powell, Grand Canyon, Chevelon Creek, Cave Creek, San Pedro River)    NM (Rio Grande, San Juan River, Jemez River)

Surirella ovata Kützing
   AZ (Grand Canyon, Central Arizona Project, Upper Lake Mary, Canyon Lake, Chevelon Creek)    NM (McAllister Lake) [According to Krammer and Lange-Bertalot this name represents two separate taxa: Surirella minuta Brébisson in Kützing, and Surirella brebissonii var. kuetzingii Krammer & Lange-Bertalot. Reexamination of specimens would be required to disambiguate the two. Nomenclatural status unclear]

Surirella ovata var. africana Cholnoky
   AZ (Grand Canyon) [Nomenclatural status unclear.]

Surirella ovata var. salina (W. Smith) Rabenhorst
   AZ (San Pedro River)

Surirella patella Kützing
   AZ (Grand Canyon, San Pedro River)

Surirella robusta Ehrenberg
   AZ (Lake Powell, West Clear Creek)

Surirella rudis Hustedt in Schmidt
   AZ (Chevelon Creek) [This name is apparently invalid.]

Surirella spiralis Kützing
   AZ (San Pedro River)

Surirella splendida (Ehrenberg) Kützing
   AZ (Rio Salado)

Surirella striatula Turpin
   AZ (Lake Powell, Grand Canyon, Cholla Lake, Chevelon Creek)    W TX (East Sandia Spring)

Surirella suecica Grunow in Van Heurck
   NM (Rio Grande)

Surirella tenera Gregory
   AZ (Southern Arizona Lakes)    NM (Conchas Lake, Rio Grande)

Surirella tenera var. nervosa Schmidt
   NM (Rio Chama)

Surirella sp. 1 NAWQA UMICH CZAB
   AZ (San Pedro River)

Synedra cyclopum Brutschy
   AZ (Hawley Lake)    NM (Charette Lake, San Juan River)

Synedra famelica Kützing
   AZ (Chevelon Creek)

Synedra fasciculata (Agardh) Kützing
   AZ (Rio Salado)

Synedra goulardi Brébisson ex Cleve & Grunow
   AZ (Rio Salado, Gila River, Rio Verde, West Clear Creek)

Synedra incisa Boyer
   AZ (Oak Creek)

Synedra minuscula Grunow in Van Heurck
   NM (Embudo Creek)

Synedra rumpens Kützing
   AZ (Oak Creek, Tonto Creek, Rio Verde, Canyon Lake)    NM (Conchas Lake, San Juan River, Elephant Butte Lake, Rio Chama, Embudo Creek, Rito de Los Frijoles, Santa Fe River, Red River, Rio Pueblo de Taos, Rio Grande)

Synedra rumpens var. familiaris (Kützing) Hustedt
   NM (Rio Chama, Conchas Lake, Rio Grande, Rio Brazos, San Juan River, Red River, Rio Pueblo de Taos)

Synedra rumpens var. meneghiniana Grunow in Van Heurck
   NM (Embudo Creek, Rio Chama, Jemez River, Santa Fe River, Red River, Rio Grande, Rio Pueblo de Taos)

Synedra rumpens var. scotica Grunow in Van Heurck
   NM (Rio Chama)

Synedra socia Wallace
   NM (San Juan River)

Synedra tenera W. Smith
   SYN: Fragilaria tenera (W. Smith) Lange-Bertalot    AZ (San Pedro River)   NM (Conchas Lake, Rio Brazos, Santa Fe River, Rio Grande)

Synedra ulna var. ramesi (Heribaud) Hustedt
   AZ (San Pedro River, West Clear Creek)    NM (Rio Chama, Rito de Los Frijoles)[If valid, this variety should be formally moved to Ulnaria]

Synedra sp. 1 NAWQA MORALES
AZ: (West Clear Creek)

Tabularia fasciculata (Agardh) Snoeijs
   SYN: Synedra fasciculata ( Agardh) Kützing    AZ (Chevelon Creek, Rio Salado, Rio Verde)    NM (Elephant Butte Lake, Ute Lake)

Tabularia tabulata (Agardh) Williams & Round
   W TX (Diamond Y Spring)

Tabularia sp. 1 NAWQA UMICH CZAB
   AZ (Rio Salado)

Terpsinoë musica Ehrenberg
   AZ (Rio Salado)    W TX (East Sandia Spring)

Tetracyclus rupestris (A. Braun) Grunow in Van Heurck
   NM (Rio Brazos)

Thalassiosira nana Lohmann
   AZ (San Pedro River)

Thalassiosira pseudonana Hasle & Heimdal
   AZ (Chevelon Creek)

Thalassiosira weissflogii (Grunow) Fryxell & Hasle
   AZ (Chevelon Creek, Rio Verde, San Pedro River)

Tryblionella acuminata W. Smith
   SYN: Nitzschia acuminata (W. Smith) Grunow    AZ (Rio Verde)    NM (Conchas Lake, Ute Lake)

Tryblionella angustata W. Smith
   SYN: Nitzschia angustata (W. Smith) Grunow in Cleve & Grunow    AZ (Grand Canyon, Chevelon Creek, Santa Cruz River, Rio Verde, West Clear Creek)    NM (Conchas Lake, Elephant Butte Lake, Rio Grande, Charette Lake, Ute Lake, Santa Rosa Lake)

Tryblionella angustata var. acuta (Grunow) Bukhtiyarova
   AZ (Lake Powell, East Verde River)

Tryblionella apiculata Gregory
   SYN: Nitzschia apiculata (Gregory) Grunow    AZ (Grand Canyon, San Pedro River, West Clear Creek)    NM (Elephant Butte Lake, Rio Grande)

Tryblionella balatonis (Grunow) D. Mann in Round et al.
   SYN: Nitzschia compressa var. balatonis (Grunow) Lange-Bertalot    NM (Rio Grande)

Tryblionella calida (Grunow in Cleve & Grunow) D. Mann in Round et al.
   SYN: Nitzschia calida Grunow in Cleve & Grunow    AZ (Grand Canyon, Cave Creek, San Pedro River, 91st Avenue WWTP, Rio Verde, West Clear Creek)

Tryblionella circumsuta (Bailey) Ralfs in Pritchard
   SYN: Nitzschia circumsuta (Bailey) Grunow    NM (Rio Grande)

Tryblionella constricta (Kützing) Poulin in Poulin et al.
   SYN: Nitzschia constricta (Kützing) Ralfs in Pritchard    AZ (Lake Powell, Queen Creek, Cave Creek, San Pedro River, Rio Salado, 91st Avenue WWTP, Santa Cruz River, Rio Verde, West Clear Creek)    NM (Conchas Lake, Charette Lake, Ute Lake, Santa Rosa Lake)

Tryblionella debilis Arnott ex O'Meara
   SYN: Nitzschia debilis (Arnott) Grunow in Cleve & Grunow, Nitzschia tryblionella var. debilis (Arnott) Hustedt    AZ (Canyon Lake, Chevelon Creek)    NM (Conchas Lake, Rito de Los Frijoles, Santa Fe River, Rio Grande)

Tryblionella gracilis W. Smith
   SYN: Nitzschia tryblionella Hantzsch in Rabenhorst    NM (Conchas Lake, Charette Lake)

Tryblionella hungarica (Grunow) Frenguelli
   SYN: Nitzschia hungarica Grunow    AZ (Lake Powell, Grand Canyon, Central Arizona Project, Chevelon Creek, San Pedro River, Rio Salado, Gila River, Santa Cruz River, Rio Verde)    NM (Charette Lake, Rio Chama, Jemez River, Santa Fe River, Rio Grande, Rio Pueblo de Taos)

Tryblionella levidensis W. Smith
   SYN: Nitzschia tryblionella var. levidensis (W. Smith) Grunow in Cleve & Grunow    AZ (Chevelon Creek, San Pedro River)    NM (Santa Fe River, Rio Grande)

Tryblionella littoralis (Grunow in Cleve & Grunow) D. Mann in Round et al.
   SYN: Nitzschia littoralis Grunow in Cleve & Grunow    AZ (San Pedro River, Rio Salado, West Clear Creek)

Tryblionella littoralis var. tergestina (Grunow) Snoeijs in Snoeijs & Balashova
   SYN: Nitzschia littoralis var. tergestina Grunow in Cleve & Grunow    AZ (Grand Canyon)

Tryblionella salinarum (Grunow) Pelletan
   SYN: Nitzschia levidensis var. salinarum (Grunow) Krammer & Lange- Bertalot    NM (Ute Lake)

Tryblionella victoriae Grunow
   SYN: Nitzschia levidensis var. victoriae Grunow    AZ (West Clear Creek)    NM (Ute Lake, Santa Rosa Lake)

Ulnaria acus (Kützing) Aboal in Aboal et al.
   SYN: Synedra acus Kützing    AZ (Grand Canyon, Central Arizona Project, Southern Arizona Lakes, Oak Creek, Upper Lake Mary, Canyon Lake, Chevelon Creek, Cave Creek, San Pedro River, Rio Salado, Rio Verde)    NM (Railroad Canyon, Rio Chama, Conchas Lake, Rio Brazos, San Juan River, Ute Lake, Santa Rosa Lake, Jemez River, Rito de Los Frijoles, Rio Grande)

Ulnaria contracta (Østrup) Morales & Vis
   SYN: Synedra ulna var. contracta Østrup    AZ (West Clear Creek)    NM (Elephant Butte Lake, Rio Grande, Rio Brazos, Rio Chama, Rito de Los Frijoles)

Ulnaria delicatissima (W. Smith) Aboal & Silva
   SYN: Synedra delicatissima W. Smith    AZ (Canyon Lake)    NM (State record)

Ulnaria delicatissima var. angustissima (Grunow) Aboal & Silva
   SYN: Synedra acus var. radians (Kützing) Hustedt    AZ (Rio Salado)    NM (Conchas Lake, McAllister Lake, Rio Brazos, San Juan River, Ute Lake, Rio Grande)

Ulnaria oxyrhynchus (Kützing) Aboal in Aboal et al.
   SYN: Synedra ulna var. oxyrhynchus (Kützing) Van Heurck    AZ (West Clear Creek)    NM (Embudo Creek, Rio Chama, Rito de Los Frijoles, Red River, Rio Grande, Rio Pueblo de Taos)

Ulnaria ulna (Nitzsch) Compère
   SYN: Synedra ulna (Nitzsch) Ehrenberg    AZ (Grand Canyon, Central Arizona Project, Oak Creek, Southern Arizona Lakes, Upper Lake Mary, Canyon Lake, Chevelon Creek, East Turkey Creek, Big Lake Outlet, Sycamore Creek, Cave Creek, Sunrise Lake, Queen Creek, East Verde River, Bartlett Lake, Rio Verde, Rio Salado, San Pedro River, Gila River, Rio Verde, West Clear Creek)    NM (State record, Carlito Spring, Railroad Canyon, Rio Chama, Elephant Butte Lake, Conchas Lake, Rio Brazos, Charette Lake, San Juan River, Aguirre Springs, Embudo Creek, Rito de Los Frijoles, Red River, Rio Grande, Rio Pueblo de Taos)    W TX (Ft. Davis CDRI, Shafter, Palo Pinto Canyon)

Ulnaria ulna var. amphirhynchus (Ehrenberg) Aboal in Aboal et al.
   SYN: Synedra ulna var. amphirhynchus (Ehrenberg) Grunow    AZ (Cave Creek, Queen Creek, East Verde River)

Ulnaria ulna var. spathulifera (Grunow in Van Heurck) Aboal in Aboal et al.
   SYN: Synedra ulna var. spathulifera Grunow in Van Heurck    AZ (Rio Verde)

Ulnaria ulna var. subaequalis (Grunow in Van Heurck) Aboal in Aboal et al.
   SYN: Synedra ulna var. subaequalis Grunow in Van Heurck    W TX (Palo Pinto Canyon)